The “hitting zone” is the area where the racquet makes contact with the ball. And as it should be, this zone is one of the most critical parts of your forehand swing. For most junior players, the hitting zone starts in front of the rear hip and continues to the point where the racquet is almost level with the front foot. Your objective should be to keep the ball on the strings for as much of that area as possible (highlighted between the racquets). The teaching pros say you can do that by hitting smoothly through the ball. The longer you can do that, the more control you will have over your shot. So you should really concentrate on the ball in that hitting zone. Although it is nearly physically impossible to actually see the ball making contact with the strings, you must do your best to do so.
This lesson is an excerpt from Bring Your Racquet: Tennis Basics for Kids