What can I say. I bought Vayne day 1 and have not looked back since. I must say she is probably my new favorite AD dps champion. This guide WILL help you get 15+ kills/game. This is my first guide so keep that in mind. Hopefully it turns out to be as helpful to you as it is successfull for me.

Marks - Desolation for sure. You want to bust into their armor early and often. Plus it'll help against those champs with Doran's Shield early as well.

Seals - I went alacrity. Nothing wrong with adding some attack speed. You could also use some crit runes as crits will be the most important thing with her. However my item build will have enough.

Glyphs - I went cooldown reduction/level with Celerity. Granted her cooldowns are really not that long but lowering that Tumble skill as low as you can is not a bad thing.

Quints - I went with more Armor pen. You could also choose to go crit but when you put these with your marks you start off with +25 armor pen which you will need.

EVERY Vayne build I have seen has Trinity Force. Im not saying its particularly bad. But it is expensive and you could be building other things that will improve her more. Trinity has a few stats you wont really need (at least with this build) so I'd rather boost up my most important attributes alot rather than boost up everything a fair amount.

Boots of swiftness obvious choice. You could go mobility I guess but I'd rather have that +3 speed at all times. Mercs are unnecessary because I have you buying Cloak and Dagger, which is the next item. It is an amazing early game item, yet still great all game. That tenacity will allow you to build boots for speed as opposed to building AGAINST the enemy team.

Next go BF sword. You need to get some damage on top of that crit chance youll have. DONT build it into Infinity's Edge before you get zeal. You'll want some more attack speed and crit before bulking it up.

NOW get your Infinity's Edge. Now you have even more crit, and you WILL crit hard, and fast. This is about where Vayne will start to take over

After this I recommend going Bloodthirster because you will need some Life steal. And you might as well throw in the damage on top of it.

After Bloodthirster you will want to build depending on the other team. If you need some more armor pen go with a Black Cleaver to cut them down. You can also go Madreds if they get tanky and dont have too much Magic Resist.If you want some health and damage you could also go with Frozen Mallet. It will give you some survivability as well as the passive slowing effect on enemy champs which is great for her. Also Wits End can be good if they are caster heavy.

Flash - Always a good spell to have. Excellent for chasing/escaping. And even though Vayne's tumble is good for both, in the event of you having to run away, if you roll the cooldown on tumble will not reset until you hit an enemy or wait 5 or 6 seconds so you may need the flash in case there are no minions around.

Teleport - Another "always useful" spell. Obviously good for defending turrets, but also good for helping prevent ganks or help gank. Just teleport in, tumble, and do her thing.

Other possible spells:

Ghost - Also good escape/chase spell. But with her roll and flash I feel those are enough. But you could substitute Flash for it.

Ignite - I will use Ignite sometimes in place of Teleport. Very good for soloing mid. Keep pinging them down with tumble until you Ignite them for that "First Blood".

PROS:

Amazing dps
Quadrakill/Pentakill potential EVERY team fight
Great chaser
Excellent mid-laner


CONS:
Squishy, plain and simple
Gets focused HARD

Solo mid: She can pretty much own any character in mid, but she will have some problems with a few champs and you'll have to play differently (LeBlanc for example). The idea is pretty straightforward. Keep using Tumble, attack the enemy champ, back up, and do it again. Sounds stupid but it works most of the time even against good players because her tumble is so quick and covers a decent distance. So get them low (1-3 cells of health depending on what lvl they are early game), then use your judgement when you think you can get them and tumble/Flash or vice versa and nuke. Plus if you took Ignite that just makes things way easier.

When on the defensive which can happen againt ranged stunners like Veigar, Sion, Annie, etc. you have to be careful with your tumble. If they catch you, they can take you down quite a bit due to your squishyness. Either wait til they are lower on mana so they cant spam on you, or just play it passive until you build your gear a little bit. When in doubt, knock them away with your Condemn.

This guide is not finished but I will have it done soon. What i have so far should be plenty to get you crushing your opponents. Check back later for the rest of the guide.