keep your eye on the ball
do underhands to hit it back (use the padal, and hit like you play golf, only don't hit the ground) if it is too low
hold the paddle above your head if it is high (that way you can hit it back)
Don't let it touch the ground.
Make sure you stand in a position in the beginning where you are equidistant from all sides and corners
Enjoy!
hope this helps