Laning 500s Grab these in order if you're new, you can also pick up Healing Rite just sell later.
I500
I500
I500
I500
I500
I500
I500
I500
Roaming 1250s Slowing bullets grab in lane if ahead, 26% weapon damage is very good. Barriers for tankiness, enduring speed for movement slow reduction. Spirit items are key for locking a target down. I recommend the first 5 in order here too.
II1250
II1250
II1250
II1250
II1250
II1250
II1250
II1250
II1750
II1250
Team Fight 3000s Mostly Components from previous items. Fortitude > Extra Health. Warp Stone because it's so good earns a spot, however I wouldn't buy it every game.
III3500
III3500
III3500
III3500
III3000
III4250
III4250
III4250
III4250
III3000
Game Ending 6200s Crippling Headshot + Diviner's Kevlar should be the first 2. Silencer if you've built into superior duration early :)