I prefer this build for mid lane,but it's usable for other lanes as well.Make sure you farm as much as you can,deny even more and play safe.Learn the range of your basics and ulti,then also get used to positionate yourself better.The terrain is very important for sniper to be a real beast.Play safe because you are very squishy until Shadow Blade.

Gank the other lanes if you can to secure kills and farm,and be careful of others ganking you.Try to even buy wards sometimes,if you feel endangered. Have fun :)