Teaching your cat to roll over requires patience, but the result can be rewarding. Remember to only approach your cat if she is in a good mood for learning. If you have a good relationship with your cat, you should be able to teach her to roll over using her favorite food and repetition.
Summon your cat to you. If she won't come when you call her name, dangle her favorite treat in front of you.
Persuade your cat to lie down. You can do this by petting her back until she lies down and relaxes, or by gently pressing her to the floor, if she is comfortable with that.
Hold your cat's favorite treats by her nose. Allow her to sniff them, then start bringing one of the treats to the other side of her body.
Say the command "roll over" while continuing to pull the treat around to the other side of the cat. She should follow the treat with her body, ideally rolling over to the other side.
Try again. Depending on how smart your cat is, she should catch on and learn to roll over as you move the food. Eventually, she should do it on command when you hold your fingers by her face and say, "Roll over."