I have chosen to obtain these items because they provide a solid start with a lot of mana. Then I get Ability power and Hp so that I can do more harm and survive longer in battles. then I only need to increase his AP in connection with obtaining spelvamp. the last item that you should get, you can choose from Void Staff, Zhonya's Hourglass and Archangel's Staff. it depends on what the opposing team plays play and what you think is good.