Truth be told, the method that I want to explain below, can apply equally to pianists of all musical styles, but the GERARD PLUTON method, which is the primary method I wish to write about has been created by a classical pianist who was experiencing many problems, due to muscular injury and tendonitis. I am including a brief history, to impress upon you the tremendous change that this style of playing can have on your ability to not only play, but also on the resulting sound.
Let's suppose you have a little melody that you want to play on a minor chord. We're only considering the notes now, not the rhythm. The pitches (scale tones relative to the key) you want to hear on this minor chord are 5 (up) - 1 (up) - b3 (down) - 2. Can you hear those in your head? It makes classical pianist no difference what key you are in. Just pick a starting pitch in your head. Do you know what song they are from (we might as well play 'Stump The Band').