Get your racket out and look at the string face. Notice particularily where there strings in the center are becoming frayed and discolored. That’s your sweet spot; the exact spot where you habitually hit the ball.

Different players have slightly different sweet spots; some are higher toward the tip, some are dead center, and some are closer to the throat. They’re all correct; especially yours.

Racket technicians love this sort of stuff. They’ll identify the exact spot and then add lead tape to the edges of the frame to the left and right of the sweet spot. This sweetens your favorite spot even more.

Two, three-inch strips (six grams) is a good place to start. Then try the racket. Better? Add more, and more until it’s too much; then back off.

Lead placed at three o’clock and nine o’clock is the most-popular place. Eleven and two is good but makes the racket a little more head-heavy. Lead at twelve o’clock adds considerable swing weight and power.
Lead can also be placed in the racket’s throat to add weight without disturbing the balance. It can also be placed under the grip to make the frame head-light.

Experiment. Lead tape is cheap and can easily be peeled away.