The moonwalk, popularised by Michael Jackson on March 25, 1983, was an obscure move in break-dancing. Jackson was only 24 years old at the time when he performed the moonwalk during his song "Billie Jean," part of ABC's 25th Motown Anniversary. It looks deceptively simple as Michael Jackson effortlessly appears to walk backwards on stage. The steps themselves are simple, but there are tips to make it easier to master the movements.
Shoes built with traction will not allow you to do the moonwalk smoothly. You need shoes with smooth soles that glide across surfaces. Tennis shoes will not work. Loafers with a smooth sole and very low traction are better. When starting out, wearing smooth dress socks will help you glide better so you get used to the fluid movements. You want to achieve the illusion that your feet are floating backwards across the surface.
A slippery floor like smooth, polished hardwood also makes gliding backwards easier. Carpeted floors create too much friction for shoes and socks no matter how slick both are. Larger spaces like gyms or dance studios allow you to practice more. You can learn to moonwalk for longer distances in such spaces as well. If you are performing, have the floor well polished before the performance to help you glide easier and more effortlessly.
Michael Jackson had both natural dance talent and training. Dance training helps you control your body's movements and it will help you move your feet when moonwalking. Michael Jackson performed using arm movements and a hat to make the dance that much smoother and more interesting. It takes practice and training to coordinate your body's movements for a smooth walk backwards. You don't necessarily need professional dance classes, but you will need to practice often.