As an Ekko main, but at the same time not a veteran to the game, i created this guide for all those people who search for a beginner Ekko's guide, but find only in depth ones.

I just wanna make clear some things which i learned from months of playing Ekko (jungle mostly) with a decent score at the end.

For junglers:
As you may already noticed, Ekko is one of those champions who scales a lot during the match and even thought he's an assassin, he can have a great impact in the match even in the late late late game.
That's why I use Dark harvest, so you can have even a better scaling. Nevertheless, it is here where there come the problems, in facts it makes you lowkey useless in the early game and forces you to farm your jungle, gank only squishies enemies and be extremely scared of invades.
Sorcery as secondary runes helps you gank lanes (you wont ever get bodyblocked by minions) and have a bit more ability haste which you wont regret in the late game.
Anyway, Ekko is a kind of based champion, that one that you will never see nerfed or buffed, so he can deal with the most part of other junglers, such as Master yi, Rammus and so on, as long as you take care of not getting stunned mid-fights and of not 1v1 tanky champs in the early game.
As a jungler you must buy Nasor's tooth as first item, as long as it helps you charging your passive so much faster.
In the end, i recommend buying tons of controls, so you can have the best map awareness (put them between dragon/baron and sidelanes, in mid's bushes and in your periferic jungle)

For midlaners:
I kinda don't like using Ekko in mid because there are too many counters, but if you have the patience for farming a bit more than usual and avoid early fights, it will pay you back in the mid-late game.
Be exremely aware of ganks and choose which runes you prefer based on your playstyle and on you laner, go conqueror if you are not sure you can always hit full combos.
Gank bot lane everytime you cane, but care of not losing too much farm.

I want, in the end, underline the importance of Ekko's main abilities: Passive and Ulti.
In facts, you passive makes you able to make every fight a one-combo fight when you have a significant amount of ap or dark harvest charges.
Be greedy in fights you can dive, go 1v2+ because your ulti gives you the chance to get back and fly away, or get a mulikill with its area damage.

(funny tip: use your w when you are invisible to the enemy so he can't see the animation until it charges up).

Have fun playing Ekko <3.