Shrapnel is a Mid Game Ability, I don't advise to get it too eraly in the game because it burns out your mana quite easily. Use it to push towers (it does damage to towers), to give some vision and to slow enemies so they don't run towards or away from you.

Headshot is Sniper's golden ablility, this skill is what ensures you get kills, with MoM's Attack Speed most Heroes die within seconds.

Take aim at level 3 is good enough to hit the tower out of the tower's range. If you can't see said tower use Shrapnel for vision.

Be carefull not to waste your ultimate, you got to do the maths of the enemies HP and the damage you make, also use it only if it is to risky to chase them or you don't have the range to kill. It also provides true sight to heroes, so it can help your team to kill invis heores.

Good for early agility. Its converter into a Wraith Band.

Better than 2 Iron Branches, because it convers into a Wraith Band. Early stats are always good.

Got to have that regen because of sniper's low HP.

Its the best item if you dont want to waste time going to base and loose precious HP and EXP.

An Iron branch that can be avoided to get a fast Wraith Band, but it is really good for early stats. Get this if you are facing a spammer mid, like Storm Spirit or Skywrath Mage.

Gives a nice boost to your stats while you farm.

Got to have that little boost on your Movement Speed, to escape a gank or to get a kill.

Get this to get some extra regen or if you are facing a spammner in you lane, like Skywrath Mage or Storm.

Get Power Treads first because you now are one of the most annoying things ever, the Attack Speed boost lets you chain stun and can grant easy kills, it also lets you switch to mana to use your Ulti.

For me this is the most awesome item to build on Sniper, the lifesteal lets you stay in the lane to farm, farm jungle and lets you team fight and solo most heroes with no fear, its also gives the attack speed most needed on Sniper.

Shadow Blade lets you run from an icomming gank or counter-gank if you use Mask of Madness.

Good because it increases Attack Speed, does some AoE Damage and it can be upgraded to a Mjollnir

Lets you do a bit more damage.

This item is mandatory because it gives you a big boost on Attack Speed and more AoE Damage.

If you got the spare gold and don't have any item in mind you can upgrade Crystalys into a Daedalus.

Do an Eye of Skadi if you feel confident about your farm and think you won't die that easly. It gives more Damage, HP and Slow. If you are going to get this sell or don't buy Desolator.

If you are against any Phatom Assassin or anyone with Butterfly get MKB.

Very, very situational because its extremely dificult to farm, but it gives good stats.

Got to have those DPS, it also gives much needed Evasion.

If you want, you can convert the Stick into a Wand, to boost stats overall and get some needed regen.

Good to deal more damage to kill enemies and farm a lot better, it also reduces your opponents armor. Not stackable with Mask of Madness.