Hi, this is my build for Vayne (IMO the best carry in LoL). It's a very offensive build that requiers you to play defensive early game til you get your CS up and then go full slayer.
As you can see I play with only AD runes wich is bit of troll but it goes hand in hand with tumble since the bonus is % of max. In lvl 1 you have 88 AD with dorans blade and it only takes about 3 tumbles to down a support. It's incredible easy to lasthit and the tumble harras should be enough to keep the lane stabil.

Also here you can see that i don't go for any defense and instead go for more movement speed that is awesome combined with Vaynes passive.

there's not much to say about the items, its a maximun damage build for Vayne. The lantern makes up for the lack of defense in the runes/masteris and it makes it easy to stay on the lane for as long as possible w/o feeling the need to b. the free ward also comes in handy when it saves a few gold for the support. When all you miss is the Bloodthirster you sell the lantern and buy that. If that should be done to and the game is still running you should sell the boots for another Phantomdancer. you loose about 40 movement speed but you smashes anything that stands in your way.

I choose to play flash/heal to minimize my deaths, ignite is also a good choice but i feel that it's unnecessary with so much dmg. Ghost isn't really needed either cuz you'll be pretty damn fast when hunting down that poor tristana.

The key to succesfully pull a build like this off is to stay hidden until the tank is in. once everyone has started you use ulti, tumble in and suprice rape.

so lets talk about Vaynes abilites. Her main ability tumble (Q) is just a great ability that gives bonus attack dmg on next attack. it's also great when hunting someone or when you escape or avoid skillshots. it's very easy to harras with it since the enemy might not even react until your next attack hits him in the crotch.

Her (W) silver bolts deals bonus magic dmg every third attack, gives her a massive dmg bonus lategame. I never choose this as my second ability since early game is for lasthitting and harrasing only and not many enemies will be stupid enough to let you take 3 shots in a row at him. it also workes perfectly with the trippel phantom dancer you will have when full geared and you'll have about 2.4 attackspeed.

Condemn (E) is the heart over i. If all of Vaynes abilities wasn't so damn awesome i would say that this was the best, it makes vayne very OP since it can be used as a stun or just to push a harrasing melee back a bit. not much more to say, push them in to some wall, stun them, and slay, simple as that :)

final hour (R)is a very good ulti, it increases vaynes attack dmg for 8/10/12 sec and makes her invis for a brief moment after every tumble, making her harder to target and get the overhand of the enemie carry. i usually stand hidden and wait 1-3 sec before going in the teamfight, not long enough for my team to die and long enough to not get nuked. pop (r) tumble in (e) the target and just continuing to tumble.