Im not building this for advice, i just fancied posting my build so i knew what others thought about my master carrier class
So have a browse and tell me what you think, this build never steered me wrong.
On Spawn Grab some boots of speed, as sniper moves very slow these are essential so you can escape combat if you are caught off guard.
Also an essential is Tango's run away and heal up, if you die this early in the game you will find it very hard to come back.
And The Iron Branch is Recommended just to give you a little buff in all areas
Aim For Gold, you dont need massive kills or EXP, Gold is your friend, but dont let my word stop you from hanging next to the creeps, you still need EXP but gold is more important
Grab Power Treads as soon as you can, and set them to Agility. this gives overall buffs, from damage to attack speed
Get Yourself A Claymore Or Shadow Amulat
Depending if you Want speed or damage
ultimately you will get the other to make your shadow blade
As You get To around level 8/9 if all goes well you should be close to having your Shadow Blade,
once you have it you need to grab maelstrom,
this will give you Chain Lightning, this is great for dealing extra damage against groups of hero's As well as creeps, increasing your damage, attack speed and income, win win win!
you should be looking at level 12/13 about now even if you havent you should get Mjollnir
again more attack speed and Chain lightening, your set for the big leagues, group up with your team and push hard on lanes, your still not stong enough to go it alone, and lets face it, as sniper you never will be, your a glass cannon, go lay down some DPS.
During Late Game Buy situational items, what ever fits the needs, more damage, more health
at this point you can start building up a tankier class, though in the case of someone such as Spirit Breaker As opp, you need more damage.
So as i said buy what works for your situation