Remember this: In to out is a downswing thought, not a backswing thought. As you swing back, try to create some room for the club to move on an in-to-out path coming down. David Leadbetter demonstrates how.
Tom Watson explains why it's important to go with your natural shot shape whenever possible. If you mostly hit slices, be more aggressive with your tee shots on dogleg-right holes. If you hook, be aggressive on dogleg lefts.