Overview of Abilities:
Vlad is a scaling champion; you're weak early but with levels and items you'll become a monster.
Your Q is a point and click "drain"; it will deal damage to the enemy and heal you. When empowered, it does almost double damage and triple healing. It begins at a 9 second cooldown, but goes to just over 2 seconds at max rank with some ability haste.
Your W will utilize current HP to make you untargetable (note this is NOT invincible; abilities like Fiddlesticks drain will continue to damage if they were started before you used your pool). You will also heal for some of the damage you do while pooled, and you can continue to channel/release your E ability. This ability also allows you to drop tower aggro/ignore tower bullets, making Vladimir great at poking under tower and diving.
Your E expends health to channel an explosion. The "max damage" on E occurs when the blood has all come into vladimir, though it can be held a small period longer if needed. You can start your E, hold E, and press W to continue building the damage and release while pooled. This is a vital mechanic that allows for dangerous combos.
Your R places a circle of blood on the ground, instantly applying a 10% damage increase (from all sources) to all enemies hit for 4 seconds. At the end of the 4 seconds, the enemies take a large chunk of damage and you'll be healed. Because this is from all sources, it's great to use early in a teamfight to give both you and your team a damage boost.
Early Game:
You are weak, and will usually lose or go even on short trades. This is okay because Vlad heals with his Q, and you can play a game of attrition in the lane. Look to keep CS up with autos/non-empowered Q while staying safe, trading with empowered Q (2 stacks on resource bar). A decent trade is using a max damage E -> auto -> Q. Always be looking to stay max range, and get aggressive on melee champions that can't all in (i.e. zed level 1/2, Katarina pre-6). NEVER COMMIT to a full fight unless you've got a large HP lead, your main goal early is to apply pressure and keep farming.
Mid Game:
Once you've got Night Harvester, if you're not really far behind you should be able to solo your enemy laner. Again, avoid all in's until you've gotten some poke and have an HP lead. Once teamfights start happening, using your ult on a solo kill is rarely worth it. Look for at least a 2 or 3 man ult.
Combo should look like as follows (with 1 stack on your resource bar before the fight): Ghost -> R (on a clump of enemies) -> Q (whatever is closest) -> E (hold) -> W -> Relase E at max buildup. You should be able to kill any squishy carry with R, max damage E, and an empowered Q.
Late Game:
Once you have Rabadons/Void Staff, you're an absolute machine. Remember that R has a 10% damage increase (from ALL sources of damage) that lasts 4 seconds. At the end, you'll deal a large chunk of damage and heal for a large amount that increases with each person hit. At this point your Q and E are both very short cooldowns and should be used regularly. You should be capable of running into fights and killing off high priority targets with no counterplay, healing at the end back to full HP and winning the fight.
Final comments:
Vladimir is not easy; There's a lot of nuance to his playstyle, combos, and teamfighting. It can feel like you're going to lose a game if you ignore rotations, but early you have to focus on getting as much gold and experience as you can. If you do, you should begin beating almost any lane opponent at 9 and overcome most leads in the game. Pool is overpowered to dodge most abilities and tower bullets. It will take time, but keep trying, play to scale, and you'll get the hang of him!
