major thing that determines the height and direction of the
ball is the angle of the racquet. The swing has some effect
on that, but not nearly as much, and body or feet position
have nothing to do in that regard.
success of the top players is due to their heightened awareness
of the racquet position at impact time. Just a small angle
variation, and the results vary quite dramatically.
so much movement around the court, the position of the racquet
is paramount and it needs to be developed at an early stage.
your racquet handling with Oscar's videos (DVDs) and book.
Learn to develop your memory as an athlete. Even what we call
mechanics can be stored at an instinct level. Like Oscar says,
play tennis "with your hands".