I assume you are trying to teach her basic heeling as opposed to a focused heel for competition. How is her food drive and drive for a ball on a string. There are many different approaches. One is to start by teaching her the static heel position which is with her sitting at your left heel. You can lure her into position with the food. Use good food, smalls pieces and make sure she is very hungry. Reinforce the correct position continuously by marking it with praise and immediately giving food. Hold several pieces of food in your left hand with your hand about where you pant's pocket is and above her head. After a short time of correct position of the static heel, give the release command and praise her up and repeat. It can take many repetitions of this training. Once she learns the static heel, start out with the moving heel only doing one step and then having her sit, luring and reinforcing with food the whole time. Then slowly progress to two steps, three steps, etc. If food doesn't work you can use a ball on a string if she is motivated for it. Tie her out on a long line to a tree, get her in drive for the ball, step into her and make a quarter turn to the left with ball above her head on the left. If she offers the correct behavior try to drop the ball so she will catch it. Then proceed starting with a single step walking in an arc around the tree. If her food or drive for the toy is not working, you basically have compulsion left. You need a correctly sized and fitted prong collar and have to know how to use it.