Have your dog at Heel (Left Side) and pretend there is a short wall between you and your dog.  Walk in a straight line for a few steps.  Now turn to face your dog as you call their name so that they turn towards you.  As soon as they start to face you start walking in the opposite direction (remember the little wall) and have your dog walk a few steps on your Right Side.

Now, turn toward your dog again as you call their name.  They should turn towards you and come into the heel position.  Walk a few steps and repeat.

You may want to dish out a treat every few steps the first few times doing this exercise.  Start off with a couple of treats in EACH HAND so you are ready when you switch sides.

This first exercise I am using food to lure my dog to follow my hand.

In this exercise my dog is following my hand without a lure.  I reward the dog by feeding him from the opposite hand as I turn and FACE him.  Very quickly your dog will learn to follow you on the correct side based on your body language and arm cues.