Everyday we say...
"This is my right hand, I raise it up high. This is my left hand, I reach to the sky. Right hand, left hand, they're hard to tell apart. But the right hand is the hand that goes over my heart." Then we go right into the Pledge of Allegiance.
In order to teach the right hand, I put a RED rubberband on each child's right wrist and I tell them, "Red is right." You just have to make sure no one takes it off to play with it or put it back on the wrong hand. A few children kept wearing it days after...