at the early of the game, you're not the one who is too strong. So do not be too aggressive. instead, you just need to focus on farming and wait for your jungler come and gank.

in the mid game, you must have the Lich Bane and the tear of goddess for increase your damage by shoting the mystic shot.

you might to asked yourself: why I build an ap ezreal but i take the infinity edge and the statikk shiv? Well, i'm gona show you ưhy: first, the statickk shiv will increase the damage from the Lich Bane and the infinity edge will give you more tons of damages to become the harasser of your team