Need Help landing W as Ekko

You need to predict what's going to happen after throwing your W out. Will they react and try to dodge it? Will they run from you if you're obviously running toward them for the stun? Would the slow suffice? Can you trick them into a trap? Can you use your ult to surprise land the stun?

A lot of Ekko's kit requires planning as well as reflexes.

One thing that helps me is to throw it behind them and then when its about to land to start chasing them. That usually works for me.

Throw Q at your enemy to slow them and look where your enemy is headed then then throw W far ahead when you predicted their movement direction, afterwards E and go in the circle...insta stun

Try going into fog of war and cast W slightly behind the opponent and engage towards him using E and Auto Attack. This can regularly work, unless the opponent ccs you and blocks you from procing your W.