There are two things that come into play that give power to your shot. One is momentum and the other is acceleration. Momentum is the force from the forward speed of the racquet, while you can increase that force considerably by accelerating the racquet.
I have been de-emphasizing momentum so people pay more attention to acceleration.
Why? This is because minimizing the backswing, or taking the racquet slowly up to the ball (or close enough), helps find it and control the shot. That usually corrects unforced errors.
Now, when you become a master at this, and your attention stays in front and not behind you, you can make your swing bigger and bigger.