You need to build carefully but steady, take mid for a change. Dont be afraid to utilize your ulti for creep kills, u can also do it in other lanes.

Get Boots + pots as starter ( Boots ugraded to Berserker's Greaves, after Wriggle's Lantern, maybe first after Doran's Blade

The get Wriggle's Lantern if possible, or just Vampiric Scepter.

If you need a little more dmg, buy a Doran's Blade, else save your money, buy B. F. Sword first.

From here on its just Bloodthirster's and more Bloodthirster's.

If you get ganked + attacked a lot, try to get Trinity Force.

For runes get flat phys. dmg, and ArP.

Summoner spells:

Flash + you choice, i would go with Ignite, or Promote for adding extra pressure in lanes, but ignite is my first prio..

I know this is not as pro. as many other guides, but please tell me how to insert items(links, with pic+text), and color text.

I know this sounds impossible, but just try it.

Just play aggressive.