For detailed information on Spectre's spells please visit http://www.playdota.com/heroes/spectre
First off let me congratulate you for wanting to play such a classic league carry. Spectre is chosen by teams to counter the enemy's aoe line-up trough dispersion, dagger and haunt. While beeing a particularly fragile hero, the specter compensates trough mobility and speed, and of course trough hp items.Let's look at some Pro's and Cons

Pros

• An aoe slow
• Mobility due to no collision on dagger's path
• An escape, a ganking and an AOE spell all in the ulti
• Very popular against aoe line-ups due to dispersion

Cons

• No jungling capabilities untill 1st core item
• Melee hero
• Fragile, without dispersion and some hp items

Skill build

1. Spectral Dagger
2. Dispersion
3. Spectral Dagger
4. Dispersion
5. Spectral Dagger
6. Haunt
7. Spectral Dagger
8. Dispersion
9. Dispersion

Follow with maxing desolate and then stats.Level haunt when ever possible.

Explanation
This is the only reasonable way to play Specter.Why in earth should you get dispersion when you have little hp early game? Ask yourself this, why get desolate when it's so situational.The hero has to have no allies in a 400 range around him, that includes creeps, summons and of course his allied heroes.First levels of the games are the laning phases, that means that most enemy players will be in their lanes, except for the gankers who of course you dont even dream of confronting. In conclusion you gain advantage of desolate in 2 cases:

• You find a jungler, one without summons or illusions
• You chase someone out of the creeps range

In the first case, even if you find someone jungling early game, heroes like Enigma, Chen or Enchantress,the most likely ones to jungle before level 5-6, can take you easily, and you neither gain the advantage of desolate because they have their minnions with them.
In the second case you end up chasing someone the short distance between their creeps and their tower, because you cant tower dive without dispersion and some hp items.

So althoug 45 damage from desolate is a nice add, you should get it at about mid game when there are more team battles, wich means chasing more heroes and that's about when the enemy start jungling.

Dispersion on the other hand gives you 20% EHP(effective health power). That means you can witshtand 20% more punishment, wich is crucial for a fragile hero like Specter, that has to farm his lane early game. Not only does it add to your surviavibility , it also makes you what you are in team battles. Compare it to Silencer's last word aura, it's your bread and butter abililty in team fights.

Item build

Starting items





Start by buying a sliper of agility, 3 gg branches,a healing salve and tangoes the rest of the money. You can take basicaly any lane, you can even handle a solo mid if you're not facing one of the stronger soloes like Tinker, Viper etc. Use the currier to keep you stocked in healing salves and also get you your items. First build poor mans shield, that should be doable in max 3 mins , and then buy 2 circlets and finaly boots. Upgrade the circlets to bracers, and also make sure to carry a tp scroll to easily escape a gang or def towers, even if you have haunt. By now you should be about level 7 and your inventory should look like this:





Next upgrade your boots to Phase Boots. Again this might seem contradictory and at first glance it is but:

1. Your images dont benefit from the atack speed of threads
2. Boots of Travel are expensive and delay your late game

Besides , the armor and damage from phase boots adds to your surviability, at least against phisical heroes as much as str threads plus the bonus ms boost helps between 2 daggers or when tower diving.

Farm yasha or ultimate orb, if you think you can farm a fast 2100 gold by all means go for the ultimate orb, in all other cases farm yasha because it comes in small affordable chunks. By late mid(30-40 mins) game you should have your first core item Manta Style. Your inventory will look like this:




You can sell the poor mans shield at any time since it's usefull only in early game. Next you have 2 options:

1. You farm diffusal blade and then go for a hearth of tarasque if the game drags on.
2. You start farming Eye of Skady

Skady is the ultimate orb effect for specter since it gives you much needed stats and a beter slow effect. Difussal on the other hand is easier and cheaper to make and is especialy usefull if the enemy has a warlock on their team. The mana burn synergizes well with Manta Style and between you and 3 iluusions, you burn mana quickly. If you go difussal , next thing farm a heart of tarasque. I take it over the butterfly since it synergizes much beter with specter and his illusions, the butterfly only giving certain aspects to illusions like agility but not the added atack speed and damage.

You can also go for a vladimir's offering if no one else is building it but you should follow one rule of the thumb: go for stat not damage items.

NOTE: Insted of poor mans shield you can go for magic wand but no queling blade. You can last hit decently without it, and in my opinion queling blade is mostly a jungling item.