I decided to make his short guide to help people stuck in low divisions to get out of there.
Actually i started playing ranked games recently and im still a bronze player but with Evelynn i started my climb reching 6 wins in a row.
If you are in my same situation and you are looking for a good champion to get out of the EVIL bronze league, maybe this guide could help you.

There are many reasons to play Evelynn in ranked games; I play her as a jungler to have the control of the map and help my mates when they are not doing great.
Let's see some of the Pros and Cons of playing Evelynn:

Pros:
-Her passive is something crazy,She's Invisible!
-Snowball easy and hard since you can gank everywhere and non-stop
-In low division people don't buy Vision Ward just because Vision Ward are expensive.
-Force people buying Vision Ward (if they do it) which are a lot expensive...2 of them cost somethink like 250g almost the same you can receive from a kill
-Hight mobility
-If you are fed you can carry games extremely well, even 1v3 fights


Cons:
-Countered hard early game by vision wards and oracle's elisir
-Fall of late game if you don't take kills and assists early
-Item dependant

Since her skills doesn't scale much with AP i recommend to focus her build on Magic Penetration items.
This is why i recommend those items.
is really overpowered on Evelynn thanks to his q's low Cool Down.
Same for who is really usefull early-mid game, for jungling and usefull in ganks since it gives you true damage.

When you play Evelynn your main focus is to gank lanes.
Thanks to her passive that will be quite easy, also because people at low elo always forget to buy Vision Wards.
Gank every lane before going back to base. Of course if a lane is winning hard you are not needed and you can focus on other lanes.

If you are doing it well you will have enough money to buy your first Spirit of the Elder Lizard quite early game and start gank again.
IMPORTANT: you always need to farm your jungle; farm is important, maybe more than kills or assist so dont forget about it.

Also important: remember that costs no mana so you can spam it to reach faster your jungler or lane, also CD is refreshed on kill or assist so try to use it to get more kills or escape from a bad situation.

This is more or less everything I have to say about Evelynn.
Just remember that every game can be won no matter your score or your team...just do your best and do not flame your mates, that won't make the game going better, teamwork will.

That's all...I hope my English is not that bad and i hope this guide will help someone with his climbing to higher tiers.

Thx
Gl & HF