First off you want to get boots, 1 health pot, 2 mana pots. Reason for the 2 mana pots first is because you can heal yourself with your second ability. The stone is a great item to have as soon as you get 800gold. It will help you survive and deal damage with you first ability with the man regen, and the extra gold doesn't hurt. Second item is the Avarice Blade, Crit chance and more gold. Next is building up the Trinity Force. You can get either of the three first depending on your enemy. Usually i get them in the order i have them in the item purchases. Next is the Hexdrinker for magic protection and dmg. Upgrade the Hexdrinker to the Maw of Malmortis which will really help your survivability pls good dmg. At this point I go for the Bloodthirster. Great item to have for living espically with your third skill maxed. Now its time to sell the stone and buy the Infinity Edge for pure crit and massive damage. The last item is for movement, crit, and Attack speed with the Phantom Dancer. At this point your first ability should be criting for well over 1100 damage with a 4 second cooldown. It is a super fun build and you will do super damage. Hope You Enjoy.