Wearing the right shoes is very important because the slide won't be achieved with perfection without the right shoes. Choose shoes with smooth soles. High heel shoes, tennis shoes, or formal shoes won't work. You need a flat and smooth base to assist you in the proper glide. If the proper shoes are not chosen, you might get jerks in your movement. You may lose balance and it will be extremely difficult to perform the move. If you don't have shoes with smooth soles, wear gym socks.
The floor on which you are performing or practicing the move must be smooth. Trying to moonwalk on carpets or concrete floor is very difficult. Look for a polished stone or wooden floor. Even smooth tiles will do. It is very important that the grip between the floor and your feet is the minimum. The step must seem effortless for the moonwalk to look elegant. If you have access to a dance studio or a gym, you can utilize the space to practice the move.
The correct position is difficult to achieve. You have to stand with a straight back and keeping your feet together. Lift the right heel and stand on your toes. Transfer the balance to the right foot in such a way that the left leg must feel weightless. Slide the left leg back and at the same time lower your right foot. The left toes must align with the right heel. Now repeat the process with the left foot. Keep alternating and you have your moonwalk.
Without practice, perfecting this particular step is a distant dream. You need to keep practicing till you get to the perfect smooth movement. The slide must look natural and the movements must be coordinated. The timing of the slide also must be perfect. All this can be achieved by practice. Record a practice session to see what flaws you are making so that you can correct them.