how do I stop doing commands that I don't want to do

[mythbust4000]

This happens to me in all games but mainly in melee so that's why it's here(and theirs no general smash forums)
Most of the time it's the c-stick and other buttons rarely do this and when it does it's a forward smash other then a tilt
So I don't want this to happen because I shffl and edge guard with c stick so if I continue to do this I will up air when edge guarding and get them back on stage so how do I stop

 

[Stride]

Practice more. There's no other solution.

If you can't do something consistently then understand where/how, specifically, you're going wrong and then change what you need to in order to improve it. If you keep doing smashes instead of tilts, then don't move the control stick as hard; if you keep moving the C-stick upwards instead of sideways, then try harder/more deliberately to move it in the direction you want.

 

[Cu29]

If it's just a bad habit, take a break from the game for one or two weeks and come back. You'll be rusty, but a lot of those bad habits will have faded. If you do this be sure not to let the habits re-form.