While not all golf instructors agree on exactly how your right elbow should move during your swing, most agree that a tucked right elbow will help you hit a draw. The key to keeping that elbow tucked is something called connection, and the key to staying connected is a good shoulder turn – or "coil," as it is sometimes called. Legendary golfer Ben Hogan recommended a drill that teaches how a tucked right elbow feels; it can be easily "stretched" to teach a full swing.
Take your club and assume your address position, with your knees gently flexed, your spine tilted forward from your hips and your weight centered over the balls of your feet. Your arms should hang in a relaxed position, your triceps will rest lightly against your chest and both of your elbows will hang a slight distance away from your chest. This "light resting" is what the term "connection" means. You want to maintain this connection throughout the drill until the steps tell you otherwise.
Turn your shoulders into your backswing until your hands are about waist high. Your elbows shouldn't bend and you shouldn't lift your hands; the forward tilt of your spine will cause your hands to move slightly upward on a plane. This movement is called a one-piece takeaway and most professional golfers make it to start their swings.
Starting at the waist-high backswing position, swing the club down through the ball position to a waist-high finish (a half-swing). Again, your arms should remain in roughly the same position they were at address. This means both triceps remain lightly against your chest throughout this half-swing, which keeps your right elbow near your side.
Practice swinging the club from one waist-high position to the other. Focus on maintaining the connection between your chest and both triceps.
Stretch this short "takeaway swing" by letting your right elbow bend on the backswing; this bend will automatically cause your wrists to cock. You should be able to lengthen this swing until your left arm is nearly parallel to the ground without losing the connection between your right tricep and chest. Your hands will be just below shoulder level.
Swing the club from your shoulder-high backswing position to a shoulder-high finish position. Your right elbow remains bent until your hands drop below waist level. At that point it straightens and remains straight for the rest of your swing; your left elbow will bend as you reach your shoulder-high finish. This mirrors your backswing, just as you did with the shorter swing. Again, both triceps will remain connected to your chest throughout this three-quarter swing.
Practice swinging the club back and forth between these new positions. This is nearly the same drill Hogan outlined in his book, "Five Lessons."
Let your right elbow move away from your side slightly at the top of your backswing position; this will increase your right elbow bend slightly and your right tricep will move slightly away from your chest. You don't want to move your elbow much; your hands should move no higher than your ear.
Start your downswing by dropping your right tricep back into its connected position against your chest. Your right elbow is now tucked and still bent, allowing your hands to drop down without making your wrists uncock early.
Keep both triceps lightly connected to your chest as you continue your downswing. When your hands drop below waist level, your right elbow – still tucked because your right tricep is connected – straightens, causing your wrists to uncock as the clubhead reaches the ball position.
Swing to your finish position. Let your left elbow bend as your left tricep "disconnects," so that your hands move to an ear-high finish. Because your right tricep remains lightly connected against your chest, your right elbow will remain straight during your followthrough.
Practice swinging the club back and forth from one extreme to the other. This will give you a good connected swing with a tucked right elbow. It also will improve the consistency of your swing.