This is my First Guide i did so i hope u will like it.
I will keep it short and try to explain it easy.

Eve is an amazing champ if u got the skills.
through out the changes in LoL eve is not longer played in mid lane but is still playable in the newest season of LoL.

She was my breakthrough to Platinium lvl and so can u ^^.(or more)

Evelynn has many benefits but also her weaksides listed below.

Pros

+ Shadow Walk is early a huge advantage because no Vision ward early on.
+ U can build to both sides (AP and AD)
+ Dark Frenzy, a good mobility ability which can help you in catching fleeing enemies
or escaping tough situations.
+ High Damage Output
+ AoE slow+shield,depending on number of enemies hit,by her ultimate Agony's Embrace
+ Abilities with low mana cost
+ Strong early game presence


Cons

-Squishy Early Game
-Close Range
-Weak to all kinds of CC,except slows
-No CC before she hits level 6,which is one of the best
strengths of a jungler, making his ganks better
-Easy Mana loss early game
-Can be easily counter jungled

1.You start most of the times at Golems Camp.(Use ur smite first at 1:55 to get their buff)

2.Next the red buff after that do the blue buff(smite will be up again wich also gives u a little health back). One exception befor u do blue buff is when a chance to gank mid or top is more favorite to u and ur team.(get kills early if poss)

3.After Normal Jungling or getting hopefully a kill Base.

4.Next are your for the Red team ganking ways never go from ur lane or follow up into a lane to initate a gank and the best is with a nice red buff to gank. (to let them flash is also good)
]

5.At lvl 6 i recommend to gank bot as much as possible if the other lanes are doing okay.
For Drake control and ending the lane and start sieging towers. (mo MOneyy).

6.VIce Versa for purple team.(ganking)

7.The Jungle item is Strongley recommend by me to ad to ur attack speed AND most important reason is the Magic attack dmg wich is STACKING in clearing big Monster in camps or getting assist's and kills .

the longer the game the stronger u get .

This is the hardest part for you.
it discerns a bad Eve from a good one.

If u got ur build by now (4 items or 3)
u have to adjust to ur team mates.

Thats because u have to play a different role in each different Team (poke, Tanky , or split pushing)

In most of the times ur going to go for their Carry's.
with BotrK and randuins they cant out run you.

But sometimes u have to be the shiled for your carry ( when u have a leona for example who goes in like SuperGirl and leaves her carry uncoverd).
You can shred through Tanks with ur BotrK and slow with ur ult and BortK also.

some times u have to Tank when u have a poke comb ( u better use ur ult good :) )

and with the Example Core build u can split push very well.
Use ur E on enemy Minions and let the magic happen ( if u have at least BotrK and The Jungle Item).
Also if u just want to take a Tower fast just E on a minion and focus the Tower it should fall fast u need most of the times at most 2 E skills on that.

So i hope you liked my short Guide to Evelynn and i hope u have fun with my build.