Stand on your left toe and right heel. Your right and left feet should be turned outward from your body. Learn to alternate balance between your left toe and right heel, and your right toe and left heel. Practice switching back and forth, keeping your upper body level.
Practice dragging the inside of your right heel, pulling into your left foot. Start on your right toe, slide your left heel horizontally to your left toe, and drag the inside of your right heel. As you drag your right heel, your left heel should push to the ground, meeting your right heel at the same time.
Drag your right heel to your left toe and curve it outward, away from your body, as it gets closer to your left heel. Right before your right heel meets your left heel, step up on your right toe. As your right heel pushes outward to the right toe, your left toe should turn inward and switch pressure to the left heel. Practice this movement until it is fluid, like spreading jam on bread. As your right heel pushes outward to the right toe, your left toe should turn inward and switch pressure to the left heel. In review, push off the right foot, slide out the left foot, pull from the left foot, and slide in the right foot.
Combine steps 2 and 3 to complete a full side moonwalk. Practice reversing directions in time with music.