I'm assuming you don't know how to slide, then hit, on clay. If true, then in singles play center the ball, especially if your opponent is a good mover and experienced clay court player. Avoid getting into sharply angled rallies, a clay court player will be happy for both of you to be running wide off the court, his footwork will beat you. You'll be running 2 or 3 feet wider than him almost every time, leaving more court open and exhausting yourself sooner from all the running. Good luck.
"In theory, there is no difference between practice and theory. In practice, there is." Lawrence Berra