I'd like to dedicate this to the beta testers of this great game because they are awesome like this guide.

Introduction to Sand King
Ganker with some aoe and lots of built in escape spells, what more could you want? Oh, he farms like a beast too.

Spells (Go look up the mana costs and cooldowns on playdota if you want them, I'm talking about them.)

Burrow Strike
Bread and butter skill, it doubles as a blink so you can use it to escape up/down hill. Aim it just like impale for max damage. Important to note here unlike blink if you click a spot beyond the range sand king won't burrow strike in that direction, instead he'll run up and then burrow strike.
Targeting the ground instead of actual heroes will not only give you more range (you can hit some heroes on the max of your range by clicking ground, if you click the hero crix will wait to get closer)but it will also let you hit multiple heroes much easier, practice with it. You'll miss a bunch at first but once its more natural to you (~1 week or so) you'll have improved as a player.

Sand Storm
Awesome defensive skill, great farming tool, and nice damage.
At level 4 it has a 10 second cooldown, 30 mana cost, and does 80 damage a second to a 550 aoe. IMBALANCE MUCH? At level 4 this clears an entire creep wave fairly quickly for the cost of 30 mana, meaning you can pretty much spam it every wave. The only reason you'd ever waste a burrow strike on a creep wave is 1) You desperatly need to push to a tower and have extra mana or 2) You're going back to base and want to use extra mana real quick.

Also this does pretty nice damage on level 3+4 so sometimes its worth it so immediately sandstorm after burrow striking a high armored hero.

Caustic Finale
Okay this skill basically has one use, soloing against melee heroes. I take one point if I'm against an all melee lane (for the most part soloing against a melee hero, like pirate/alchemist/etc)

But what, this skill is for farming you say? I clear a creep wave for 30 mana. While being invisible. Yeah, its not so hot. Unless you're facing the likes of broodmother (even then, I wouldn't yell at you for skipping this, sandstorm ftw)
Skip this skill for stats unless you're soloing middle vs a melee!

Epicenter
Landing these usually means you won the teamfight, grats. They're harder to land without a blink dagger but not at all impossible. It should be noted that even though some heroes have a stun if you land a burrow strike on them they'll still be too slow to land it.
Lina + Lesh is an example of this. You can do it on DK too but its much trickier because you have to get close to him and then burrow strike through him out of his stun range.

Once you have a blink dagger walk out of sight but inside blink range, hit epicenter Then press down shift. While holding down shift hit the blink dagger and click where you wanna shoot towards. Also useful to walk into fog and then cast epicenter, if you time it right the opponent will walk right into your epicenter.
Skill Build
1 Burrow Strike / *Sand Storm / **Caustic
2 Sand Storm / Burrow Strike
3 Burrow Strike
4 Sand Storm
5 Burrow Strike
6 Epicenter
7 Burrow Strike
8 Sand Storm
9 Sand Storm
10 Stats
11 Epicenter
12 Stats
13 Stats
14 Stats
15 Stats
16 Epicenter
17+ Stats
*When you're playing defensive from level 1 sometimes a sandstorm is more beneficial, 80% burrow strike strike is better though.
** If you're soloing against a melee, only get one point then resume normal build. He'll learn to dodge your caustic and the other spells are better!
Items
Starting: Tengox2, 1 carity, 1 magic stick, 3x branch
(if you're soloing middle I suggest tengo, flask, quelling, 3x branch)
Shoot For: Bottle, Blink Dagger
Next: Boots of Travel, Sceptor
Extensions: Guinsoo

Justification:
Wand is awesome, bottle for mana so you can gank. Blink dagger for setting up nice epicenters