Do you have trouble, when you try to rush the net, moving into position for the first volley? Do you wonder how you should move and where you should be?
If you do, think of the way you played hopscotch as a child. Remember how you'd run, pause, then jump to either side into one of the marked squares on the pavement.
If you're having trouble getting to the net in tennis, pretend there's a hopscotch board painted on the court surface. Do the same things the hopscotch player does when you head toward the net.
Run up quickly toward those imaginary squares. Then pause momentarily as your opponent returns your shot. Decide where the return is going, then move diagonally to that side at once, as a hopscotch player does. That move should put you in position for your first volley.