Hi!I am a Gold II ADC main.My favorite ad carries are Vayne,Graves,Lucian,Corki and Ezreal.
Today I decided to make a Vayne guide because in my opinion I am a decent Vayne player so why not give a try? :D

Pros
-A lot of mid-late game damage.
-Scales pretty good in late.
-Even when behind in early,if you play corectly you can comeback in mid-late game and become a beast.

Cons
-Weak early game
-Not that easy to play.

The runes are the same runes that you want to use on every ADC.Attack speed quintessences for that early attack speed that can help you farm.
AD Marks-if we are not running ad quints we really need ad so the best rune type for ad is the marks type.
Armor seals-we need the armor for the trades with the enemy ad carries or ad assasins.
MR Glyphs-The most of the supports and mid laners are working on magic damage,so taking magic resist helps you in the trades with them.

Pretty standard masteries.
4 points in fury because on every ad carry you need the attack speed.
2 points in Warlord because Vayne is not a caster ad carry so you don't need the Blade and Spell Weaving masteries.
The 9 points in defence just gives you the health and the reduced damage from enemy champions,which you really want.

Flash-as Vayne you don't have any escape(altough you can push your enemies with your E,that is not an escape)
Heal-The most common spell for ad carries because of the bonus health that you can get in the fights with assasins or even in laning phase.

Since Vayne is one of the most hard ad carries to play,she requires a lot of mechanics and good positioning.Her early game is pretty bad.So I don't recommend you to play her in solo queue JUST if you think you can do it corectly.

Basically in early game you just need to farm untill you have your Blade of the Ruined King.After that,you need to balance the farming time with the fights time.

Blade of the Ruined King-It gives you ad(thing that you clearly need on every ad carry) and attack speed(very important on Vayne) and Life Steal for the survive ability in fights.
Berserker's Greaves-Basically the best choice for upgraded boots for Vayne.As I mentioned before,the attack speed on Vayne is very important because her W passive is your main source of damage and her AD scalling aren't that great so you will focus more on attack speed.
Phantom Dancer-Attacks Speed,Critical Strike Chance(more damage) and movement speed for faster roaming/escapes
Infinity Edge-Altough Vayne doesn't need that much AD it's still good because of the crit chance and the passive.
Bloodthirster-Same as I.E.,the passive is very OP,the survive ability is increased.
As Defensive item,you can choose G.A. if u need hybrid resistance.Banshee if they have a heavy ap composition and Mercurial Schimitar if they have strong CC.