Oh, Those Clunky Strokes
You can use a rubber band or an official vibration dampener. You can hold the racquet with three hands. But if you hit off-center, your stick will announce the miss-hit with a hideous clunk and try to shake out of your grip. So much for that over-size racquet and its huge sweet spot.
The primary culprit for miss-hit strokes is bad eye-contact. Given the great, good fortune that your head is connected to your body, when you glance up, it's not just your head that goes up or down, but all of you, including your racquet. On a volley or a ground stroke, because the peeking glance is upward to see if your shot is in, the racquet lifts and the off-center hit is at the bottom edge of the frame. Those ones really rattle in your hand. On a serve, overhead or high-volley, the peek is downward, and the off-center hits are at the top of the frame. In either case, it's not that you're not holding tight enough but that your not watching long enough. Your head should be motionless during your stroke. If it is, the sweet spot will be right where you're aiming.
The other typical miss-hit is at the throat of the racquet on a ground stroke. This unhappy clunk comes from crowding the ball, the most common of all position problems. Crowding comes from not turning your shoulders enough on the backswing so that your gaze and contact point are adequately at your side. Try hitting down-the-line to cure this problem. If you're not turned enough, and therefore crowded, your shot will only go cross-court.
c Keith Shein