One of the greatest pleasures was meeting Larry Holmes who taught me the guy who throws straight punches will probably win the fight. Larry didn't like hooks instead he preferred the right-hand behind the jab. The key to getting the right-hand off is the following.
Larry says that you gotta get close to the opponent and be in position to get the right-hand off. This is done by placing the rear heel behind the right armpit. This placement does two things it moves your body forward. Secondly it rounds out the shoulders making it easier to salute with the right-hand. Larry told me that guys who throw hooks are easy to beat. So throw the right-hand in a saluting manner and turn your thumb over the right elbow must point upwards. Most people don't know this.