This is going to be a guide on how to play Vladimir.
Vladimir is an AP champion which excels in controlling a lane and 1v1 fights

Skills

Crimson Pact

His passive gives him 1 point in AP for every 25 points in health and 2 points in health for every 1 point in AP.

Its very important that you know that his passive doesn't stack.

Transfusion

Vladimir drains the lifeforce of his target, dealing 70 / 115 / 160 / 205 / 250 (+60% of ability power) magic damage
Transfusion's Healing - 15 / 25 / 35 / 45 / 55 (+0.25 per ability power).

This is going to be your most used spell. It deals a great amount of damage and it also has some nice spell vamp especially with the build I use.

Sanguine Pool

Vladimir sinks into a pool of blood for 2.5 seconds, becoming untargetable and slowing enemies above him by 50%.

Vladmir deals 15% of his bonus Health in magic damage over the duration and heals himself for 12.5% of that amount.

This is one of the best escape spells in the game. When you pool you cannot be targeted and spells such as karth's ulti will not touch you.
use this spell wisely as it costs 20% of your current life so be sure that pooling is beneficial.

Tides of Blood

Vladimir unleashes a torrent of blood dealing 60 / 90 / 120 / 150 / 180 (+45% of ability power) magic damage to nearby enemies.

Each cast gives him an Empowered stack (max 4), increasing his healing and regeneration by 8% each. Additionally, his next Tides of Blood deals 25% more damage and costs 50% more Health per stack.

This spell is especially useful for farming and late game team fights. It has a very low CD even at lvl 1. Also the stacking is not something to take for granted. You should always build up your stacks before a team fight, because the extra dmg will help a lot.

Hemoplague

Vladimir infects the target area with a virulent plague. Affected enemies take 10 / 14 / 18% increased damage for 5 seconds.

This is one of the most beneficial ultimate's to have in a team fight. It doesn't only deal dmg but it also affects enemies to take bonus dmg which is great for an organized team in team fights.

Runes

For Marks I take magic penetrationThis is a must for any caster especially a nuker.

For Glyphs I take flat ability powerYou can also take cooldown reduction blues but i like the early AP for harassing and with this build you already get some nice CD.

For Seals I take heath per LvlThis is great because it gives you some nice health and it also procs your passive. you can switch these out for flat AP or flat HP.

For Quints I take flat ability powerVery good for early game harassing but you can also take flat HP quints.

Masteries

For masteries I go 9/0/21 getting the mag pen in offense and all the non manna utility.
u can also go 9/21/0 if you're going for a more tanky build.

For summoner spells you should useand
Ghost is useful on Vlad because ghost affect's his W spell and you will also be using it to chase other player and slowing them with your pool.

I like ignite on Vlad because it stacks with his ultimate and it will often times give you the kill.

You can also use,orbut other summoner spells are basically useless.

Vladimir is a great solo mid champion so that should be where you play him.
you should start withand 3xBe sure to focus on last hitting at least for the first few levels because Vladimir is a very item dependent champion and he needs the gold to get thing done.

You shouldn't have to go back until you have a good amount of gold.
For your fist item you should rushand start building either youror your.
The cooldown from the boots will greatly help your harassing abilities especially against a squishy opponent such as a dps carry or a mage.

If you're having a great game and have lots of gold, you should rush your Rabadon's deathcap. If you get it early your Q will hit like a truck but remember you will get focused when the enemy sees what items you have you start building defensive items next.

One of the best item you can get for Vladimir is Rylai's Crystal ScepterIt gives you health and AP along with a very nice slow and remember it also procs your passive so all around very useful.
Another item similar to Rylai's is the Haunting Guiseit gives you some nice health and AP along with 20% spell penetration which is never a bad thing.

The last item is all up to you. It's very important that you know how the game is going and where you're falling behind. So if the team is stacking magic resistance you should consider either the Haunting Guise or maybe Abyssal Scepter. If you're lacking in survivability you should consider getting Randuin's Omenif the enemy does physical damage or Force of Natureif they're magic heavy.
But as I said the item is up to you. You need to know how the game is going and react accordingly.

harass with your Q often and hard because even if the opponent get a shot off at you you can still heal up pretty quick with your spell vamp and Q spell.

when you're ready to finish the enemy champion use the R-->Q-->E-->Ignite-->W
When you come out of the pool your spells should be ready for use and just repeat he process.

Your role in team fights is very important.
Initiate with your ultimate which will give your team a big advantage because the extra damage helps a lot. After your ult just continue to spam your spells and pool when you need to dodge or slow someone but be careful because the CD on sanguine pool isn't as short as your Q and E spells so save it for your escape or for the chase.

Vlad is one of the best champions in the game if you know how to play him.
Be sure to dominate your lane and get an advantage early on either in kills or in creep score.
People often times focus only on killing enemy champions but minion kills are as important if not more important, so be sure to last hit as best you can.
Vlad is a very powerful champion and people know that that is why they will try to stay away from you. Use that to zone them out from getting gold and experience and believe me if you get the advantage in gold and levels the kills will just fall into your hands.

Remember your place in team fights. Vlad is especially good in an organized team or a team that has a lot of AoE so if you play with your friends try to come up with a team that suits that kind of a play style and you will prevail.

Use Vladimir wisely and I hope to see you on the Fields of Justice.