I want to start off by saying I am no master at this. I have tried many different Evelynn builds and have not yet found a favorite one. This build however is probably my top pick due to the amount of sheer joy I get when i Crit the enemies bar away. This build is by no means fancy but I always get around 20 kills fairly easy when I get the core build. So it has to work yeah?

Anyway AD/Crit mixed with her passive(cloaky) plays out nicely for suprise ganks. You will want to rush to get Spirit Stone, Wriggle's Lantern, and Boots of swiftness. Reason being, first two items will allow for some excellent jungling and maintaining your health in between ganks. Boots for the extra rush with your W. I prefer to use W -> R -> E -> Q (or just w,e,q if saving or no Ult) So boots are critical to get yourself on top of your enemy as well as for the getaway. (Now it may just be the games I play but I find Most people will try to run away if an Evelynn comes tearing out of nowhere right next to them. Tis why I rush boots for the extra chase.)

Later on if you have the gold to do so, getting Bloodthirster isnt a bad idea. Your E gives you an attack speed boost and can help maintain health during a gank.

Ultimately I try to build two Infinity Edges, Trinity Force, Boots of swiftness(alacrity), Bloodthirster, and another Trinity force if I have been fed. Honestly As long as you have two Infinity Edges, and Boots you should do fairly well.

I have no idea what or how to finish this guide with all that talk about runes and stuff. So long going short...I prefer that rune set up because I haven't had problems with it so far. Do what you think is good just keep in mind that you want as much AD as possible with attack speed being another good one to do. Anyway, I hope this build works for you. Most people I share it with enjoy it. SO...ENJOY!