Compose a simple prelude for piano. Light and peaceful, yet not too slow. Stick to traditional functional harmony (chromaticism is fine as long as there remains discernable pitch centers). Heterophonic texture will work best here (melody with subordinate accompaniment).
Now go back and add a single pitch to each harmony. The added pitch should be of “mild” dissonance against the prevailing harmony.
How do you feel about the result? Sometimes, adding just a hint of “spice” can do the trick to turn the bland into something grand.