One of the most creative things you can do to make your songs more interesting as a piano player is to use chord substitutions. Instead of playing the same old chords everyone else uses, why not create your own combinations?
It freshens up a song harmonically and redefines the melody.
Here is a short video example of how to use chord substitutions using Silent Night as an example:
Click on this link learn how to do this to Christmas Carols such as Silent Night.
And click on this link for the definitive course in Chord Substitions.