the way I taught my dogs to heal was to take a long lead hold it my right hand with dog on left put a good bit of slack in your left hand start walking the dog when he(she) moves out in front of you say heal and put the lead over your head as you turn and walk in the oppisite direction of the dog he will keep walking forward until out if lead where he has to turn and catch up with you going the other way after a few times of this he will stick close as to know where you are going I have tried this method many times all without failure. let me know if this works for you.
GSPatton