I recommend the use of a clicker for this exercise.
In Rally Obedience, you need your dog to sit directly in front of you as well as on your left side in heel position. Lets start with the front sit. There is no need to yank up on the dogs neck while you push down on his hind end, although this method of compulsion training may need to be used on a dog that is not food or toy motivated.
Instead, have a treat in your right or left hand and, palm up, hold the treat over the dogs head, luring him so his head is up. Using canine physics (head goes up, hind end goes down) your dog will sit. Say “sit” when his hind end hits the ground, and then click and treat. If you don’t have or want to use a clicker, just say the word “yes” instead of clicking the instant his butt hits the ground. Be sure not to say sit until he actually sits, otherwise you are giving the word sit to the behavior of standing. Timing is everything.
After about 3 or 4 days, you should be able to say your cue word sit before the behavior and your dog should sit. If he looks at you blankly, give him a little help with a hand signal. Know that your dog isn’t stupid. He just may be more focused on your body than your words.
Practice this with your dog in front of you in proper front position. Do not lure him with your hands into position-for now, you go to proper front position. Let’s teach him what the right picture looks like for now. Which is you standing straight, the dog directly in front of you, looking adoringly into each others eyes, with your hands down at your sides. Practice front for a few minutes per day during your training. Move from room to room. Do not practice in only one location.
Your dog will now need to learn that the heel position is as valuable as the front position. Start with your dog in front of you. You go to heel position. Stand up straight, head pointed forward, chin slightly down, left arm at your waist.
“Click” or say “yes” and treat him just for looking at the right picture. Repeat this again and again, one right after the other. Your dog may try to get into front position because he has been so heavily reinforced for this in the past. Don’t get angry with him-just have him sit, you move back to heel position and start again. I like to start this training off with rapid clicks and treats because of this potential problem. Usually after a few minutes the dog will stop moving to the front as he starts learning that the heel position also pays off. Make sure you are clicking and treating him for looking up at your face. For a few minutes per day, rotate practicing heel position with the front position. Be sure that your posture is correct.
Practice in front of a mirror if you need to. It is important that your position be accurate because we are trying to teach the dog what the perfect picture looks like.