I've tried a lot of different builds for vlad but this is the one thats worked the best for me so far so i thought i share it, this is my first post so go easy on me.

For the mage build it helps a lot to start with as much ap as possible for the first few levels so the 5 ability power quintesences helps a lot. the cooldown is mostly for the pre lvl 9 stage but im sure i dont need to explain how much that 10 sec cooldown for transfusion hurts early on.

I've played with this section a lot trying to get it to how i like it. the point into ignite in the offense tree is awesome for low level and losing the summoner ability cool down reduction dosnt hurt that much.

Getting spirit visage is a huge game changer for Vlad the extra 20% health return on transfusion keeps you in your lane longer and last through those long team fights so much easier plus the cooldown reduction makes it a vital early game piece. Will of the Ancients is huge, the spell vamp combined with spirit visage will keep you full health easy. The 2 deathcaps (even tho the tool wont let me link them) the first one is great the second is to stack more ability power which is harder to get with vlad seeing as he has no other relevant stats that most of the items depend on.

For the first few levels dont be too aggressive mainly just work your transfusion when u can, try and keep ignite on cooldown the extra 10 ability power from the mastery point will help alot. By level 6 when you get Hemoplague you should be able to effectively burn an enemy, at level 9 when your cooldown for transfusion is 2 sec then it starts getting fun, by end game if all goes well i've gotten my ability power to over 900 and transfusion hits for ungodly amounts.
Vlad is overall one of my favorite champs he combines the killing power of some of the stronger dps with the survivability of a tank, hes a bit tougher to get used to but its worth it.