Practicing your hitting off of a tee will help to improve those line-drive fundamentals that get results at the plate. Of course, the point of this drill is to get the baseball bat from a comfortable resting point to the point of contact as efficiently and as accurately as possible. The ball is always placed at the ideal point of contact in the hitting zone for an inside, down the middle, or outside pitch. Undeniably, this will train your muscles to remember the correct swing for those various points of contact because it is something that should be done repetitiously everyday. You will develop an excellent, but more important a consistent swing. Getting set up in a position to hit the ball with authority will be automatic.
Placing the tee at every point in the strike zone is very important to maximize the drill. Don't forget, when practicing to hit the ball to opposite fields, you want to let the pitch move deeper into the hitting zone before making contact. That is why you place the tee on the back portion of the plate. Put the tee over the middle of the plate to simulate a pitch down the middle and work on hitting the ball straight up the middle 'through the box'. The keyis to get a good feel for your swing directed at any type of pitch anywhere in the hitting zone.
As far as the elevation of the tee you should change it back and forth from high to low, allowing your body and hands to feel the various points of correct contact. Typically, you want to raise the tee as high as possible in your strike zone because it will train you to keep your hands up and 'strong' throughout your swing. It can help to eliminate any unwanted dropping of the hands and back shoulder. Picture your shoulders as an 'airplane' trying to land. You would want the wings of the plane to be level as you hit the runway and it is the same for your shoulders when hitting a baseball. If you find yourself hitting the tee at all or popping the ball up off the tee, it is an indicator that you are dropping your hands or shoulder or both.