DISCLAIMER! FIRST BUILD HERE I HOPE TO LEARN HOW TO BETTER MY BUILD AND HOW TO BETTER OTHERS BUILD!!!!!!!!
In otherwords give me contructive feedback and minimum flame please ;)
Ok so incase you haven't notice public players (and even some ranked players) don't use an attack speed Vayne EVER! Yeah yudodat? Pretty much this guide shows you that Vayne isn't as much of an AD champ but more of an TD champ (True Damage)

Armor Penn-Let's face it Vayne needs armor penn (mainly for the begining) since her other two shots do actually count for attack damagae and at the begning it'd be nice to do as much damage as possible!
Cool Down Reduction-Why would you want this? Oh idk condemn takes for ever to get off of CD allows you to tumble SO OFTEN(especially early game) and your ult cd needs to be lowered >_>
Attack Speed-Lolz you read the intro?

PROS!
Destroys the oppenents quickly
Tanks die easily
Get over that thornmail hinderance
I LOVE TO HUNT!
Assasin

CONS!
Yeah you're squishy.
Get carried away in the chase and realize there's a turret blasting your face =(

These items are more or less designed to make you faster!
The leinancy Now you may replace Black Cleaver with Phantoms and what not but more or less Madreds ASAP!
Madred's Blood RazorFricken made for a Vayne! If you haven't read the itme description on this item........do it! MUST HAVE FOR ANY VAYNE
Banshee's Veil is jut a suggestion replace this with anything else if you don't think it's useful...Whether it be Spirit Visage, Thorn Mail, Quick Silver Sash, or even more Life Steal

STARKS Frevor Let's face it Vayne is squishy and needs life steal. I offer you Starks Fervor for the sole reason of Lifesteal + armor reduct + aura + attack speed + health regen......did I make my point?

Sword of the DivineEr is this item too OP for Vayne? I never see players use it with any champion! Ok yeah it sucks that it's active armor penn(I guess?)and makes you undodgeable? WAIT THIS ITEM IS NOTHING BUT GREAT! what ever but it gives crazy attack speed! So well since this is an attack speed Vayne buy this item.

Night Hunter Vayne's passive makes her great for chasing.....Oh wait.......No it makes her one of the best chasers in the game....I mean +40 movement speed? Gimme me moar feed plox.
Tumble75% bonus damage also makes you look pro as you dodge......anything. 'Nuff said
Silver Bolt70 additional attack damage and 8% the targets health dealt as true damage....Do the math....Vayne with 2.5 attack speed+silver bolt means any champion is dead in a matter of seconds.
Condem This is a nice spell used to stun or get away from an oppenent although it takes a little while to cast it's still infinetly useful to you.
Final HourSo this is where you win. Makes you invisible whilst tumbling for 1.5 seconds lasts 12 seconds 4x movement speed added from your passive and also 75 increased AD

The spells I would consider using are Teleport, Ignite, Flash, Ghost, Exhaust, and Cleanse. I can't really imagine many other summoner spells being useful to Vayne since she's more about the short hunt rather than the drag on battles so flash, ghost, and exhaust for running or hunting. Ignite for runners I suppose. Cleanse, you see that CC on your face? Lol me neither! Lastly teleport to either surprise oppenents back dooring or stop destruction of your turrets.

Tumble, Tumble, then Tumble again! Use your ult when it's up and Condemn when you're able to stun or need to flee....It's kind of silly to ask the skill sequence for Vayne since it's mostly just auto attack and tumble!

Yeah.....Pretty much just farm. Don't fight anyone you can't win against early on....ie a good mord vs you or anything with too much CC. You can reck mostly anyone else using exhaust though especially with Silver Bolts in hand. I don't reccomend turret diving or straight out charging for your oppenet at this point but if you realize this guy has no idea what's up.....Destroy this punk.

FARM MORE THAN YOU DID PREVIOUSLY! GRAB JUNGLE BUFFS! If you're jungler allows you to or just walk into the other jungle lol. Also......I forgot to mention.......you're a champion of ganking hide in some river bushes pop ult, tumble, and condem...auto attack till you win and repeat....do that VURRY OFTEN! During this part of the game! Turret dive not often but if the enemy has like 150 hp and 2 bolt rings....tumble and murder that guy. If you're losing hard core however just farm. Don't do anything too ballsy if team mates clearly need help, help them out.

This is usually just team battles although you'll notice you can actually chase! This is where you need to be carefule and not get carried away by the turrets! Now at this point in the game I highly encourage turret dives......as long as you KNOW ABSOLUTELY KNOW! You can murder that champion in 2 seconds or less! If you can't that turret will annhilate you just as fast as you kill the enemy. Notice you're squishy btw....You're done if you get Focused let's face it....if your enemies aren't morons they'll target you...if this happens build either Thornmail, Guardians, or Force of Nature. Whatever you need to stay alive longer! Otherwise sit in the back kill who ever you want whenever you want and claim victory!
I don't reccomend 1 on 1 this late in the game however!

Vayne is a great DPS hero that can evade the pesky thornmail but in return she has no slows, a stun requiring the environments help, low armor/hp, and a short stealth.
You must practice your tumbles to evade the enemy, let's face it getting the jump on your enemy can make or break your game. You either do it right from practice or do it wrong and ruin your KDR.