So, Vladimir IS late game champion and you should really focus on getting leveled up and getting minion kills. You actually can and should last hit with q to get sure minion kills from further distance.

You should slowly harass enemies health with q and keep your health near at maximum. When you choose to engage, you should max your e stacks before that to get the maximum amount of damage to the enemy.

I choose these items to solo top cause I prefer making Vladimir tanky champion so it can last in teamfights better but still making some damage too. Will of ancients gives little bit damage and gives a lot of sustain so you can level up without going back all the time AND it makes "tides of blood" free from taking health away.

Warmog really helps with sustain at top lane and gives you better position to challenge enemy champion. Zhonya's hourglass helps in later teamfights bringing ap and chance to save yourself if the enemy team is stupid enough to focus you.

Sorceress shoes helps you with the damage output at early and late game but you can try changin them to mercury's treads if enemy team has much croud control.

Rylai's crystal scepter gives you health and croud control so enemies can't escape so easily. Rabadon's deathcap is normal item for every ap caster and it helps rise ap which also brings health. Health doesn't only make Vladimir stronger but it really helps to do high damage with "sanguine pool".

I've used this in my every ranked game and it have never dissapointed me. The main thin is to play safe at starting.