Start thinking from the big picture: your posture.
Think about your seat bones, firmly situated on the piano bench. Your feet are securely grounded to the floor, the distance between them being somewhat wider than your bottom. In this position you can move your body side to side, transferring the body weight from left seat bone to right seat bone, and right seat bone to left seat bone.
Think about straightening your back, starting slowly from your lower back, gradually up to your mid-back and finally your upper back.
Think and feel your body weight. Is it in the middle, to the front or to the back of your torso? Try to keep it more to the front, do not leave it to the back as there is no support and connection to your arms, hands and fingers, making it much harder to play.
Think about your shoulders: I have noticed many of you, my dear students, have this problem of rounding your shoulders in and forward! Broadening your shoulders, out and to the side. Relax the shoulders down instead of shrugging them and tense them up. Feel the connection from your shoulder blades and shoulder joint sockets and channel the energy down to your arms, hands and fingers.
Think about activating your upper arms to provide support to your forearms, which are commonly and easily abused by too much tightening of one set of their muscles and no releasing and transferring of the energy.
Think about your fingers’ connections to your palms and your wrists. Fingers are often over activated (due to all those “finger independence” exercises misused by or given to abuse many students) and cause tension in the palms, wrists and forearms.
Think big motion of the whole body, not just small movement by the fingers.
Think broad heavy round sound, not small acute harsh sound.
So starting from today:
Think Big, Use Big Muscles, Make Big Sound.