>>43239657It took me a couple years of playing against my college's best players to get his speed down to muscle memory. Like most characters you should be using A-attacks more than anything, usually fast-fall nair's and pivoted-bairs are his best. You've got him down once u-airs and even fairs connect every time.
Fun thing to also learn is how to gimp with hydro-pump. Normally you space with the water shuriken, but pumps against the floor shoot single water balls that, if they hit, set up for the easiest fairs. Only go for full pumps if it can cockblock recovery or send them into dangerzones, since you're wide open otherwise.
For anything advanced, watch iStudying videos. He plays probably the best Greninja possible.