Originally Posted by Quasar
Watch Nadal. You will never see him hitting from a closed stance, always open. And he is rather effective.
Very true, and a good point. Many of the top professionals hit from an open stance - and most of the others are half-open.
You don't see too many winning players out there today hitting out of the closed stance. It just doesn't have as big a following as open does. (For the record, I hit an open stance forehand and a closed stance 2HBH)
To answer the OP, one piece of advice that has helped me is to think of the ball as very, very heavy. To move such a heavy ball across the court, it makes me remember that I need to move forward into the ball.