If you do not have a Bass/Organ player: Cover the Bass line with LH, doing chords with the RH. Some higher chord voicings with the LH are okay, to give variety.
If you have a Bass/Organ player: They will cover the Bass line, so you can play less. Try chords with your LH, voiced in the octave right below Middle C. Mostly inverted/rootless. Then the RH can also do chords higher up, or riffs and runs in between vocals. If LH chords are too complicated, start with the bass line (root chord notes - letters of the chord symbols), but play them an octave UP from where the Bass sounds. You don't want to intrude on the Bass' territory.