1) Try to play a song you know very well with your right hand “tied” behind your back.
Not literally, of course. But basically try to play on your left hand what you’d normally play on your right hand. It seems like an easy task but if you’re not used to utilizing the left hand like this, it will be a pretty big challenge.
(Don’t worry about the bass note… this is just an exercise, not a performance. You’ll only be playing chords or essentially whatever you’d play on your right hand. For a good half-hour to an hour, the right hand should be completely unused — it probably needs the break).