Hello, my name is cupofwater and I am a high diamond AD player. Vayne is my favorite champion to play, and hopefully I can give you a little insight into how to play her. She can be one of the hardest ADs to learn, mostly due to her weak laning phase and position-heavy playstyle. Once mastered, however, she is a huge threat and incredibly difficult to deal with. Hopefully this will be a fairly comprehensive guide. I will be adding onto it throughout the next few days, so check back if you want to read more. Thanks!

Marks:

Although I have experimented with attack speed and armor pen, I feel that flat AD is the most effective mark to run. Your tumble has a nifty AD ratio that synergizes well with them, and it makes last hitting a breeze. I have had good success with attack speed, due to silver bolts scaling so well with it. If you want to try that, you could run any mix of AD or attack speed marks, but I run AD almost every game now.

Seals:

Flat armor, nuff said. The damage reduced from your opponents auto attacks is very valuable, and these will help you all game, vs. not only the enemy AD but other AD champions, minions, jungle champs, and towers.

Glyphs:

Scaling MR is my personal choice, however it is worth nothing that flat MR can serve you well in lane vs. heavy magic damage comps, such as Lulu/Ezreal, Zyra/MF, etc. I usually run scaling MR against those lanes anyway for the better late game, but flat MR works too. I've also toyed with attack speed glyphs, and they seem okay, but I value the resists over the small offensive power. Again, personal preference here. Another rune worth noting is the mana regen glyph. If you are opting to not take meditation in the utility tree, running 2-5 mana regen glyphs can help your lane sustain a lot. I opt for this occasionally when it's a rough lane that I want to take 9 in the defense tree.

Quints:

Lifesteal quints are FANTASTIC against every lane, I've found. I prefer to run 6%, but 4% and 2% are viable as well if you want to play more offensively. You can also run full AD if you are confident in your lane mechanics and want to trade better with the enemy AD, however if you make a bad trade or take too much poke, you can really screw yourself early game.

Below is my standard, default mastery page. It includes all of the damage increasing masteries in the offensive tree, the mana regen from the utility tree which is incredibly helpful for spamming tumble in lane to cs, trade, and dodge skillshots with, and gives you a nice HP and armor boost from the defensive tree, as well as improved Barrier/Cleanse. You can substitute points from Havoc into increased minion or tower damage if you prefer those. Butcher can be a great talent if you need some help farming. I take it in matchups occasionally, too.
Below this is the next page, which gives you increased summoner spell cooldown and buff mastery. This is typically taken when you want to play more aggressively, using your spells for kills and opting to not take the defensive masteries. You can also substitute the point in buff duration for the biscuit, which is a very interesting choice. It gives you a nice bit of sustain in very early levels.

And finally, the last page is a much more defensive version of the first two. You get the full armor mastery, and the +30 HP Veteran's Scars. You can opt to use this page if you fear heavy harass in a lane, such as vs. a Cait. It is worth noting that 2-5 mana regen glyphs can be very nice in conjunction with this mastery build to help with your lack of mana regen from the utility tree. They aren't necessary, however. You just need to watch your mana pool without them.

All three of the above pages have their uses, however I do prefer the first one in most situations. Consider trying them all and use whatever fits your playstyle best.