I will not take 10 min. of your time to explain vlad's story, but i'll make a small introduction about how vlad is amazing, and easy to play.

First you must understand that vlad is far from a tank, use rammus or shen to tank, don't get vlad and expect to tank with, he's horrible.

Second, understand that you must use your ulti in the middle of the fight, or also to engage the fight, probly the ennemi wont remember that his plague will infest and causing 14% increased damage for 5 seconds. But don't waste ur ulti, make sure ur team will engage the fight ;)

Finally some don't like my build, but as soon as u reach lvl 9 and u got enough money to buy rabadon, the rest is so easy to get (hextech revolver are 1330 each).

I'll explain how to use Vlad as ap carry and how to rape those *****es with this (ok I admit) OP char

The item order is the best I've try. I try many combinaison and I really like this one, to be start, mid and late game carry.

Rylai is the only items that give you more hp (it also give ap don't worry) you while be less squishy and I like this items with his Unique Power. Passive dealing spell damage slows the target's Movement Speed by 35% for 1.5 seconds (15% for multi-target and damage-over-time spells). It's almost like if you had 3 slow spell and this while give you the time to make the last hit or cast your ulti if the ennemy is running away.

Rabadon is a must with every caster, so please don't ask me why I use it, and how to use it ! Buy it and enjoy all the ap !

I will explain down here why I bought 2 hextech revolver, just remember 20% spell vamp is amazing with vlad, and 50% at the end is just SO AWESOME !

Because I use ability power runes (instead of magic pen) Sorcerer shoes are a must. You can't kill a tank without those. If their is something you can change in this build might be this, instead of 27 runes of ap, get some of magic pen and get Iona shoe's to reduce your cooldown. I really prefer the ap that gives my 27 runes instead of magic pen because at start this extra ap his so usefull to make more damage and heal urself more with transfusion. Those extra ap are many times the difference between dead and kill at start.

At the end, Lich bane while give you a nuke shot ! Mixed with hextech gunblade, you while reach 159 dmg at lvl 18. Add your 594 ap at ur melee attak (each 2 sec. after casting a spell) you while reach 753 ad. U'll see in the skill sequence/use what combinaison u must use, and how strong it is.

The skill sequence with vlad is not a surprise, and almost every vlad his this.

I suggess you get mid, like almost every one suggess, because as soon as you get lvl 9, the 2,6 sec. cooldown of your transfusion spell give you a big advantage over almost all ennemies.
If you don't have mid, You can start your skill sequence with sanguine pool if u start with a ad carry like xin or jax, by slowing ur ennemy (don't cast ur pool when u engage the fight, wait until you are low hp to runeaway safety or when ur ennemy try to evade). After, use the same skill sequence and get transfusion instead of pool at lvl 2.

An other important move is to not forget to use as often as possible ur 3rd skill (Tides of blood), use it to get some minions kill and to increase ur hp regen. Remember that each cast gives him an Empowered stack (max 4), increasing his healing and regeneration by 8% each. so your healing with transfusion and pool can be increase by 32% (transfusion at lvl 18 and all ap bonus while give you 278,52 instead of 211 without 4 stack, if you add the 50% spell vamp (gunblade + will) that giving you an aditionnal 400 spell vamp instead of 303,2 without 4 stack), and those 4 stacks may give you up to 164 more hp with 1 transfusion.

Something I'd like to add with my previous calcul is that vlad can heal himself up to 679 in one transfusion (400 from spell vamp and 278 from transfusion). Something clear is that with 500 hp left vlad is not close to die. To understand how to use it, just remember that if ur low, transfusing a minions while grant you more than 600 hp. If someone run after you, drain some minions (with transfuse) or if he's quite low, 1. tides of blood 2. transfuse 3. pool (on him to slow and heal urself) 4. tide 5. transfuse. With this combination you while give ur teamate some time to come and get the ennemy or at least get closer to your tower and get something like 700 or 800 more hp to survive, also remember that while u pool he can't attack you.

Here is the ultimate combinaison u can cast on ur ennemy. You while probly kill all squishy char with this, and during all this process you while be untargetable (pool) most of the part.
1.tides of blood (447 ap dmg to everyone near you)
2. transfusion (606 ap dmg + aproximatly 500 healing)
3. normal attack (make sure you while attack champions not minions XD, and remember lich bane, as I explain you while do 753 ad dmg and heal by 150 with gunblade 20% life steal)
4. pool ( aproximatly 400 ap dmg and slow ennemy, AND untargetable for 2 seconds, this while give tides of blood and transfusion to be ready once you jump out of ur pool)
5. tides of blood (447 ap dmg to everyone near you)
6. transfusion (606 ap dmg + aproximatly 500 healing)
7. normal attack (753 ad, liche bane cooldown is 3 sec.)
let's make some math (once more)
447+606+753+200 (calculate half dmg because u probly wont be 100% under ennemies) + 447+606+753 = 3812 dmg, let's say veigar, ashe, and all those squishy char are dead :)
and this take aproximatly 4 sec with a 2sec untargetable. Also You can add youy ultimate (you should cast first for the 14% increasd dmg) and you have 765 aditional magical dmg for a great total of 4577 (1500 physical + 3000 magical)

Farming with vlad can't be easyer, you can stay near minions and avode melee figther with your transfusion or tide to get some minions last hit. Also if action got to hot, you can back easy with your pool.

Vlad is op ! Don't forget that he's not a tank and I try many build with vlad and never find a good one, the simple reason is that he don't have any skills to increase armor or something like that.
Try to make sure their will be at least one melee ad carry in your team and one good tank. also remember that ur tough and range, so protect squishy poeple like veigar.

If you can't get mid try to mixt with ad and someone with stun or slow ! (2 slow better than 1)

Have fun with my build, and if you have any comment/better build/something to add I'd like to have some comments (try to stay constructive)

and sorry, I don't speak english often so my english is poor...