Vladimir is a well rounded champ. He has great escape mechanism, great AoE spells and great nukes. It happens to any champ you play, if you want to play him/her well, take advantage of what your champ has, and try to avoid attempting what it does worst. Generally, Vlad can be played in three different builds: a ap build, tank build or a hybrid. I personally prefer using a tank build because I think that it focuses on what Vlad needs the most: Health and defence. This build works better when you have a lot of spell casting enemies.

Pros:

Great escape mechanism
Great AoE spells and ult
Great farmer
Great pusher
Low cooldowns

Cons:

Consumes health for spells
Weak disabling spells (e.g. stun, snare, silence)
Squishy in early game

I chose 21 points on defensive masteries obviously because I'm doing a tank build. I pick the points on defense that do not require mana since Vlad does not have a mana bar (He uses his health to cast most of his spells). You might ask why focus so much on dodge instead of magic resistance or armor? the answer is simple, because it dodges both magic AND physical damage which is more effective than choosing only magic resistance or armor. Picking defense against minions is fairly useless since you have a low cooldown Q for constant healing. Down the offensive masteries, I pick ap and magic pen for more damage with your spells.

I pick ignite because it works perfectly with Hemoplague, the increased damage makes your ignite even more deadly. Ghost because it works with sanguine pool. you can take zero damage(excluding the health cost of the spell)if you ghost>escape with sanquine pool in any situation. For chasing, Sanguine pool slows the enemy, and ghost speeds you up, resulting a great speed advantage. Additionally, ghost helps you to perform the sequence I'm going to state below more effectively.

Since Transfusion is a free spell (no cost) and has a very low cool down, you would want to max it out as quickly as possible for keeping your health up throughout the game. After getting lv 1 sanguine pool on champ lv2 (Note: getting the first lv of W, is very important because it let's you escape from any danger or any gank in the early game. And since it is in the early game you wouldn't want to max W out so quickly because it is VERY blood consuming which you would not want to use it for harassment in early game), and Q again on champ lv3, it is reasonable to pick tides of blood (E)on champ lv 4. It helps you to farm creeps effectively (one advantage of E is that it uses not a lot of blood). Hemoplague is your ult. It is quite a long range AoE ult which I think is a very good ult. It is deadly not only because of the magic damage it gives after 5 seconds to infected enemies but also because of the increased damage the enemy would take during the infection. After getting your ult, you can start to attempt nuking the enemy you're laning with. When you see them half or less health, you can use the following sequence: ult>ghost>pool(get in front)>tides>Trans>ignite>ult blows>dead. The sequence above might sound a bit complicated and wasting, but it is necessary in early game because all of you do not have much ap yet to do huge damage for each spell. After you've maxed out your transfusion, you can add in additional steps in the sequence to make sure a definate kill(s): ult>ghost>Trans>pool(get in front)>tides>Trans(it should be available again since it has a low cool down and a cool down reduction in runes)>ignite>ult blows>dead.

I met a lot of people choosing ruby crystal as their first item. I though think that regrowth pendant works better for early farming. Reason behind is that restoring your health is more important than having a higher amount of health in early game. Regenerating health let's you stay on the lane longer for farming gold. Since Vlad does not need mana, you can stay on the lane as long as you want before you have enough gold to buy items as long as you can keep up your health. Even if you really run low in health, a potion could help you to stay longer on lane. After quite a while farming (around 1000 to 2000 gold) I suggest you buy Warmog's Armor. Since Vlad uses health to cast spells, Health IS his ammo. And this is where I love Vlad's passive: converting health to ap and ap to health. Buying health not only decreases your chances of dying but also increases your damage output. I personally think that ap builds for Vlad are not as relevant because the health that you receive from buying ap are much less than the ap you gain from buying health.

Mercury threads for reducing disability effects such as stuns, slows and snares and it also gives you magic resistance, a great choice. After you quite an amount of health and magic resist, you can buy soul stealer to increase damage output. you do not have to worry about not having enough health yet because warmog gives you additional health as you farm more creeps.
There is a problem with tank sometimes is that your damage output is often low if you mainly purchase health, armor or magic resist. Abyssal Scepter solves that problem along with Vlad's passive. Reducing the magic resist of enemies that surrounds you is great since you have three AoE spells, it also means increasing your magic damage and magic resist.

At mid/late game, you have to increase your defence even more because this is when team fights normally start. Force of nature provides an incredible amount of magic resist which keeps you alive in team fights, the longer you stay alive during team fights, the more you can help the team or even win that particular team fight.

The last item I chose is deathcap, at this stage, increasing your health on defence is no longer necessary. You should then focus on the damage output. If you have a lot of stacks in soul stealer, deathcap increases your ap even more. You can hardly die but at the same time deal quite a great amount of damage to enemies.

As I have mentioned earlier in the description and in the title, this tank build works better when you have a lot of spell casting enemies. However, you can always adapt to the situation by replacing magic resist items with armor. It works the similar. The health can still stay the same since it is important for your survival and damage output.

Finally have fun with Vlad!! He is a great and fun champ to play. Not OP but a balanced and well rounded champ.