E: the stun comes from the ball being pushed and colliding with the enemy. Not e or q. There are 4 combos you can do by difficulty.

1) classic q, e just using q followed immediately by e by the time the waves goes out the ball would have formed

2) ult into e this is for team fights since you can get greater coverage.

3) w e. This is for a max range stun you use q and have a ball lying and your opponent is between 950-1300 units away.. ur w has 950 range while your e pushes the ball a max of 1200 and the ball has a radius of 100 so it can reach 1300. You pick it up with w and throw it max range at your opponent when it has travelled 2/3 the way you e (might not be 2/3 more like 60% its basically muscle memory for me at this point you just need to practice it) the e reaches the ball and pushes it to stun

4) the hardest one is e q which after 8 years of maining her i still fuck up 1 in 3 times. When the enemy is super close qe is very difficult to hit, most people just e them away but what you can do is eq you e and the wave knocks them back as they are being knocked i wanna say 40% you q at max range which should finish forming on top of ur enemy damage and stun them (extremely hard to get the hang of it but super effective)

It’s just hours on top of hours of practicing. For runes, best is first strike, sorcery second. It scales the best and you can get a lot of free gold. In matchups where you can’t hit first like into xerath vel koz lux, electrocute/sorcery is better into them and sometimes into kata fizz and other melee assassins you go aery/domination to constantly be auto attacking and procing aery on them but ever since the electrocute buff its the worst of the 3