When it comes to songwriting, for me the best results always has come down to a simple acoustic instrument (piano/guitar) along with the human voice. Trouble is, when you constantly go back to those same old chord progressions, you find yourself just rewriting something from a couple months or years ago. No es bueno! Sometimes the answer is to just feel around for voicings without really thinking too much about them. Let your fingers do the walking and open up the palette a bit. Those open chords might send you down a new path melodically where you arrive at a work that feels completely new for you.