How to do a knuckleball

You want to put your non kicking foot next to the ball and take 4 steps back. Then you want to run up to the ball on your toes and put your non kicking foot where it was before then kick.

This is where you want to hit the ball. Not to high (or else the ball will go straight down), not to low (or else the ball will go to high) but with the inside of your foot.

You want the ball to go uuuppp then down (this tricks the goalkeeper).

Practice this a couple of times and you will get the hang of it.