What to do about jaw clicking?

Possible TMJs are strained; ligaments to TMJ (temporomandinilar joint, or the the jaw joint) too lax.  Did you have recent dental work, cleaning done?  Do you have pain?
Generally jaw rest will help.  For a period of time avoid opening mouth wider than that is required to cause the click.  Say > 1” and avoid chewing excessively (gum, steaks, raw hard vegetables and fruits) for 6 weeks.  This will allow the TMJ ligaments time to tighten up.