1) Vladimir is a tanky mage, leaning towards the dps type (archetypes: Karthus, Cassiopeia). He loves prolongued fights, because of his rather weak burst but low cooldowns. He scales well as fights get stretched over longer periods of time.

2) He should be doing what he can, like all champions. Help your team destroy the ennemy nexus. If you're wondering what he's good at: he has an abusable laning phase, but if he gets through this he is one of the hardest snowballing champions in the game. Once he gets ahead in lane he can choose to keep shoving it out morgana-style, or just deny his opponents off the creep wave entirely.
The great difficulty of Vladimir is deciding which early game setup (runes, masteries, starting item) you're going to take. There are several viable options that all influence your laning phase in different ways.

3) Top or mid. People "prefer" him top right now, but I'm guessing that has more to do with top players doing so than with actual experience. Also mind there are very little players who are actually good at bot top and mid. Anyway, he has some insane hardcounters which he should avoid at all costs (and they're mages, which might be why some people don't pick him mid much), but beyond that he's an amazing pick in either lane.

4) That really depends. Once he can start denying his laning opponent is when he gets strong. When that happens depends largely on matchups and player skill. He should aim to actively deny his opponent at this point OR powerpush the lane and steal jungle camps. Both tactics abuse the fact that when given free roam, he snowballs into a monster.

5) In longer sustained fights he is a monstrosity. His Q and E deal good damage, and the lack of significant cooldown mean Vladimir is a sick source of magic damage pummeling your team. His ultimate amplifying his team's initiation is pretty annoying too, and the fact that you need a serious investment to actually kill a vlad is an issue as well. Mind he's also a very strong pick against dps mages in general, as he can outskirmish them due to him not relying on skillshots, and he still scales as hard as them into the lategame.

6) Smart players can avoid getting killed by him. But NOT getting zoned. You can still try to zone and deny your opponents when you get ahead, and it leaves them just as crippled, and you get complete free farm. Getting a kill with vlad usually means you'll have to bait opponents into something.

Omg i cant believe that you just said vlad sucks. He is worth what u paid for, you might not know how to take advantage of his strenghts but he is super strong top champ. Against ad brusiers he easily outdamages them with his ranged harrass. The best thing its that its super hard for them to kill you. Just back n harrass, if they tower dive you just R-E-Q-W. If u do that under tower it will wreck them.. with your ulti the tower damage is amazing.

In team fights your main job is not to go in first. Ur job is to use your skills n back off. If they dont attack u just keep auto attacking or pool under them n use ur skills again. If ur getting focused then pool away. I almost always go positive with him. But i always get over 200 cs even in short games. Watch that dyrus guy he has amazing vlad videos.

I outline all of this information in my guide, if you want a serious in-depth look at him from a skilled Vladimir player.

Guide currently has 2.8million views and four build paths on it, each different.

Not going to link it directly, but Google "Incendiax Vladimir" if you're interested. If you have questions, feel free to shoot me a message on the website.