How to be solid against consistent hard hitters?

I have played a couple of tournaments so far, and I am at a pretty advanced stage of tennis.

I can hit the ball hard, add heavy topspin, and have descent placement. One of my strengths is a big serve and strong forehand. My backhand is a downfall to my game, and I sometimes have lousy footwork.

When I play pushers I am mostly consistent, and let them cough up a short one and finish it. But right now I am facing a couple of people who are consistent, have a big serve, and can still hit the ball extremely hard, with solid placement.

I do have more stamina then these guys and I try to move them back and forth, but sometimes their shots are so good that they are clean winners.

Once I even tried to take be more of a moonballer and hit it to their back hand, which is the person's really weakness. He did lose a couple of points, but still managed to hit them back with less pace, but still deep.

This guy also comes up to the net and tries to finish out the points, but he is not that effective. What is the best strategy to play against this guy?

I really need help because I might have to play many people like this in the future.

Thanks...