The second Dorans is only necessary if you are doing badly on the lane, if you are doing OK, go for needlessly large rod. This is just a guide for items to buy. By level 16+ you can upgrade the philosopher stone for the extra tenacity, you get rilay scepter before morello if you are having problems and need to be a little more bulky. I just love philosopher's tone because you can lane longer after exchanges with the enemy that does not kill you , you wont have to stay in lane with 10% of your life, until you die and you don't have to go back.Get blue as much as possible. I use smart cast for all my spells, hard to master but worth it. I use this build on all AP champions, you will have close to 600 AP by lvl 18....and since all spells do aoe you will make the difference. If enemy stacks magic rezist, get a void staff.