Possibly the worst advice anyone can get is to keep their head down during the swing, this completely restricts the turn, you want to keep your head centered not down, so that you can make a centered pivot with no sway or spine angle break down
Practice swinging through to your finish position and holding for five seconds to achieve straighter and longer shots
Make a long, lazy, slow-paced swing to create a high trajectory. This gets the ball up high so that it lands softly and does not roll. It is a risky shot, so only play it once you have practiced it sufficiently.