Sometimes as composers we become so obsessed with the tones that we lose sight of the fact that they owe much of their impact to silence.
Experiment with using a pallet that includes silence as one of your “colors.” Begin with very simple, small figures surrounded by long silences. As the piece moves along, you might have the sound fragments expand, very gradually, in length, complexity, and dynamic level. Then, taper off so the end of the piece is much like the beginning. Let the last fragment melt into oblivion.