Phantom Lancer is my favorite hard carry - he is great fun to play when he gets his items and he is such a great, lategame powerhouse. It never gets old to see images pop up left and right when you are right-clicking your enemy.
When Phantom Lancer gets his farm, he has a very large presence on the map along with his illusion-pushing power that is simply amazing lategame.
This guide is meant for inhouse players--it will teach you (assuming that you don't already know) which items to get, when to get them, and how to be more effective at playing Phantom Lancer.

Note: Please keep in mind that I try to avoid stating the obvious in the hero counters section, where most people tend to list generic disablers as counters. Heroes, such as Lion, have been discussed as counters ad nauseum. Lastly, I am not, in any way, trying to say that I am pro. Some people, after seeing the words "competitive," immediately assume that I am a wannabe pro. This is not the case - this guide is simply meant for people who play inhouses. Because I'm assuming that you play inhouses, this guide will lack a gameplay section because I assume that this should be easy enough for you to figure out on your own. If you want a guide on how carries should be played in certain stages of the game, I suggest you refer to the Miscellaneous Guide Section.

Strengths & Weaknesses
When to Pick Phantom Lancer
Hero Statistics
Hero Abilities
Skill Build
Item Build & Rejected Items
Good Allies & Hero Synergy
Bad Enemies
Item Counters
Replays

Strengths:

• Lategame beast
• Good attack animation
• Synergizes well with a lot of heroes
• Effective harasser in-lane with the proper laning partners
• Good agility gain
• Excellent pusher - large presence on the map
• Can win a fight without even being there

Weaknesses:

• Cleave/constant sources of aoe hurt(s) him
• Fragile early game
• A little more item dependent than other carries
• Is inflexible in regards to item build choices
• His escape mechanism is easily countered
• Low base movespeed
• Melee

• The enemy has a lot of blink-dagger initiators
• You want a lategame pushing beast

Spirit Lance


Doppelwalk


Juxtapose


Phantom Edge

• Common Build
• Stats Build

Level 01 - Doppelwalk
Level 02 - Spirit Lance
Level 03 - Spirit Lance
Level 04 - Doppelwalk
Level 05 - Spirit Lance
Level 06 - Doppelwalk
Level 07 - Spirit Lance
Level 08 - Doppelwalk
Level 09 - Juxtapose / Phantom Edge
Level 10 - Phantom Edge / Juxtapose
Level 11 - Phantom Edge
Level 12 - Juxtapose
Level 13 - Juxtapose
Level 14 - Juxtapose
Level 15 - Stats
Level 16 - Phantom Edge

Justification: Doppelwalk is normally gotten at level 1 because you rarely need a nuke at level 1--you then max out spirit lance for better early game power. DO NOT GET PHANTOM EDGE AT LEVEL 6. Some people say "phantom edge must be gotten at level 6 because it provides magic-resistance." Yes, it does provide magic resistance, but that's kind of useless at this very early stage of the game and given the bad hp you have. If you want survivability, get stats instead.

Level 01 - Doppelwalk
Level 02 - Spirit Lance
Level 03 - Spirit Lance
Level 04 - Stats
Level 05 - Spirit Lance
Level 06 - Stats
Level 07 - Spirit Lance
Level 08 - Stats
Level 09 - Juxtapose / Phantom Edge
Level 10 - Phantom Edge / Juxtapose
Level 11 - Phantom Edge
Level 12 - Juxtapose
Level 13 - Juxtapose
Level 14 - Juxtapose
Level 15 - Stats
Level 16 - Phantom Edge

Justification: This build is just as acceptable as the common build. Arguably, you only need to put one level into doppelwalk--you probably aren't going to get ganked more than once every 30 seconds. Getting early stats provides more survivability, last-hitting power, and a bigger mana pool for harassing with your lance.

Starting


Quelling Blade: For last-hitting and juking. You can get a ring of protection instead, but some ranged heroes with good base damage might outhit you if you do so (if your support isn't harassing properly - or if you're playing a pub). Note: IF YOU ARE FULLY CONFIDENT WITH PL'S GREAT BASE DAMAGE THEN FEEL FREE TO NOT GET QUELLING BLADE (you could go for slippers to convert them to PMS instead).
Ironwood Branches: For stats and to later upgrade to a magic wand. Stats obviously provide better survivability as opposed to no stats, and starting out with branches is much more cost-effective.
Salve: Merely for the HP regeneration. Try to only use it if you need the regeneration quickly.
Tangoes: For over-time HP regeneration. These shouldn't need an explanation.

Core

Main


Treads: Treads should be in your core because it provides cheap stats and is more lategame dps oriented (you should obviously have BOTs at some point too - treads just come first).
Magic Wand: It's just a great item in general, and people with escape mechanisms like PL are especially good holders of magic wand because it provides that burst mana and health for more survivability (along with cheap stats).
Radiance: You should definitely rush a Radiance, and get it around the 20-25 minute mark (depending on whether or not you get Vanguard). It's a great item on PL is because it is:

1. Great for pushing in tandem with your illusions.
2. Annoying for blink initiators on the other team.
3. Great on good chasers, like you.

If you cannot rush radiance in time, and if your farm is going to be delayed, get a diffusal blade first instead. Or if they have an Ursa on the other team, you will want to get diffusal blade before radiance.
Ring of Basilius: Is awesome on Phantom Lancer in the early-mid game, because it allows you to spam your lance more freely in-lane, and is also good for regening your mana for doppelwalk to avoid ganks. NOTE: RoB IS NOT FOR VLAD'S.
TP Scroll: Regardless of the hero you are playing - you should ALWAYS carry a TP scroll on you. You may think: "well, wouldn't that delay from getting my radiance?" The answer, put simply, is no. The reasons why you should always have one on you are:

1. You can teleport to any lane for more freefarming
2. Great for avoiding ganks, especially if someone brings dust
3. The mobility that it offers, in general, is a must-have for any hero

Extension
OR

Vanguard: You should probably get Vanguard before Radiance - unless if you are totally confident that your team can watch your back while you are farming. You are, after all, a low hp hero who can definitely make full use of the survivability that Vanguard offers. In all honesty, this item is not just for Axe--it's great item that can be gotten on practically any melee hero because it offers insane survivability against physical damage. If you try to get radiance first, your farm might be delayed from dying too easily to gankers. People always assume that getting Vanguard delays from the rest of his core--this is completely wrong. If anything, getting Vanguard first will allow you to get your core faster since you will be dying a lot less than a Phantom Lancer without Vanguard. Note: YES, I KNOW THAT IMAGES DO NOT BENEFIT FROM THE DAMAGE BLOCK ON VANGUARD. THAT IS NOT THE POINT. VANGUARD IS SIMPLY FOR THE HP AND SURVIVABILITY OF THE REAL PL UNTIL HE GETS HIS HEART.
Poor Man's Shield: Cheap and effective. You can get this instead of Vanguard, but keep in mind that you are skipping the health component of Vanguard, as well as a higher damage block (On average, Vanguard blocks 28 damage). Another thing that PMS lacks in comparison to Vanguard is regen, a component that I consider invaluable to hardcarries like PL.
Bottle: You can use the Crow-Bottle method to regen your health and mana pool. Bottle costs only 600 gold, and this method is pretty effective - especially in-lane. Just keep in mind that if you don't get bottle, then your mana will regen much more slowly, even with a Ring of Basilius.

Luxury


Diffusal Blade: Diffusal Blade should come right after Radiance or Vanguard - the feedback orb that it gives in conjunction with your images is amazing. Not only is the feedback simply awesome on PL, but purge is just a great skill all by itself. And to top it all off, it's cheap! Only 3300 gold.
Manta Style: Increases the number of illusions that you are capable of producing, and of course synergizes with Diffusal Blade. In general, it's a great, stat-buff DPS item. Some people say: "PL doesn't need manta because he already gains enough dps from his illusions." This is retarded reasoning. Why else do you think that manta is in Naga Siren's core? Manta is simply a great DPS item in general that is gotten for most agility carries for all the reasons just listed.
Butterfly: The item that almost any agility carry should have. And of course, it synergizes with Juxtapose and Phantom Edge because of the immense attack speed bonus that it offers. Evasion is also a great lategame skill. I shouldn't even have to explain why this is a good luxury item for PL.
Heart of Tarrasque: Despite the fact that your illusions take 450% extra damage, HoT still makes them pretty tanky. HoT is considered your core luxury because there tends to be a lot of aoe, so making your illusions last longer is vital for PL to have a much larger influence in team fights.

Situational


Monkey King Bar: If the other team has a lot of evasion / chance-to-miss skills, then MKB might be a good choice. I would only swap out Radiance for this - however, you should only do this if there are no blink-dagger initiators and if you already have enough pushing power on your team.

Maybe...


Buriza: Buriza offers a lot of DPS on PL. But getting Buriza kind of defeats the purpose of playing a deceitful hero. You are supposed to confuse your enemy with your illusions - buriza doesn't let you do this because your illusions will crit in smaller numbers (because they don't benefit from raw damage--go test this in single-player mode if you don't believe me).

Rejected


Vladmir's Offering: If you seriously considered buying this, ask yourself this question: "am I playing in a pub?" If yes, then take a look at the rest of your teammates' items--there's a 95% chance that all of them are holding one, so don't even bother buying Vlad's since you can just mooch off of your teammates. I see this all the time in pubs, and yet they don't realize that Vlad's is perhaps the worst possible item you could get for Pl. By all means, let a support get it, but don't detract from PL's dps capability by wasting an item slot on Vlad's - you are not Ursa or AM. Just because you are a diffusal blade holder it doesn't mean that you should get a life-steal aura to complement the mana burn. There are a countless number of other items that can fit the bill better than Vlad's can.
Battlefury: They say that whenever you buy Battlefury for PL, a baby dies. PL is maybe perhaps the worst battlefury-holder in the game - even some ranged heroes are better holders for it than PL. I hear some newer players argue that it complements his pushing power - even if illusions could cleave, which they can't, it would still suck on PL because illusions do not benefit from raw damage.
Cranium Basher: Illusions do not benefit from the bash that CB offers. It also offers raw damage which illusions do not benefit from. In summary, it's a pretty bad investment on PL.
Stygian Desolator: This is a pretty popular item for PL... in pubs. Yes, it grants a negative armor buff that illusions can benefit from (assuming that the real PL hit the enemy hero with it in a certain time frame), but it's a mid game item and PL is a lategame hero. And of course, illusions do not benefit from raw damage.
Sange and Yasha: This is also a really popular pub item. Don't get it for Phantom Lancer. This shouldn't be considered a cheap replacement for Manta, because SnY is like Skadi - which also shouldn't be gotten for PL. The maim isn't needed because you are already a good chaser, and Manta offers much more dps. Avoid getting SnY at all costs.

"The Asian Lane Partner" & The Other Mana Battery


Keeper of the Light: The PL + KotL duo is one of the most famous laning setups ever. Period. This lane was made famous by the Asian scene a while back, and there are several reasons that make it a good lane. In short, the idea behind this lane is for KotL to feed mana to PL with Chakra so that PL can nuke the brains out of those laning against him. It's great for harassing because Spirit Lance's cooldown is 7 seconds and it has a long range of 750.
Crystal Maiden: She's a great ally for anyone anyways - she can also fulfill KotL's role to a degree. She also makes up for KotL's weakness, which is his lack of a disable.

Negative Armor Buffers


Vengeful Spirit: Simply put, she is an amazing support. Her Wave of Terror is great for maphax and your illusions, obviously, benefit from the armor reduction (especially since Diffusal Blade's feedback deals physical damage).
Slardar: Amplify damage makes it seem like your illusions do the damage of an actual hero. Not only is there a damage benefit, there is also a chasing benefit. Since Amplify Damage provides vision of the target, it makes it so that people like SA/NA/Invoker can't run away from you (assuming that people like SA were picked in competitive play).
Dazzle: Dazzle's ultimate is a huge steroid to your illusion's dps (and your own, of course). He is also a great in-lane partner because he has a heal and his Shallow Grave is great for saving people who are getting ganked.
Bristleback: His Viscous Nasal Goo is good for your illusions, and it slows your enemy even more.
Alchemist: Acid Spray is good for your illusions. He also benefits from you. With Spirit Lance, it is hard to lose vision of your target - therefore allowing Alchemist to stun an enemy and not himself.
Razor: His ultimate reduces armor. He also benefits from you in the same way that Alchemist does; your Spirit Lance makes it possible for all of the lightning strikes from his Eye of the Storm to hit his target.

Cleavers / Splash Damage / Axe & Centaur


Truesight


Evasion & Percent Chance Miss Spells


Him


Earthshaker: Even though you have added magic resistance, his ultimate dishes out a lot of damage if there are a lot of units around (hint: your illusions are breakfast for him). Also, his fissure can separate you from your illusions, which will severely hamper your dps.

Truesight


Battlefury


DPS counters

Pro Games

FTD vs Kingsurf

• This is an extremely famous replay of ZSMJ - a Chinese player known for his farming skill. The game is pretty long, but it's worth it. From this game, you can learn how to farm effectively, and also about PL's item order. Keep in mind that ZSMJ didn't upgrade his RoH to a Vanguard because his team ensured a fast radiance.
• Raw Replay File Download

Blight.USA vs EG

• EG.Miley plays a good Phantom Lancer in this game. He opts for diffusal first, but you must realize that diffusal blade is a situational first choice. He also didn't go vanguard because it would have been a little useless in that situation. But overall, it's a quick game. (Merlini is in this replay by the way ).
• Raw Replay File Download

Pubbie Inhouses

NRQ vs TpeD

• My team (NRQ) played against some Peruvian team with a really long name that I managed to shorten to TpeD. This is in the Razer Global Challenge (RGC) of 2010. I didn't play Phantom Lancer that game, but I played Slardar (I did terrible this game, because the Sand King took the pleasure of always counter-initiating me). But Snackalicious makes some pretty good item choices, and you can model his gameplay to an extent (just don't model his cs). I also know what you're thinking (assuming that you're looking at the laning) - wtf PL solo top?! He soloed top because our VS didn't listen and roamed instead, feeding ftw (along with me - just try to ignore me this game) .