When I hear a clicking, my routine is to stand up and pedal to see if it's coming from the seat area. If the noise continues, I will check/tighten both quick releases. Next, I will take the pedals off a put a little lube/grease on the spindles and put them back on. If it was the seat area, I will pull the seat off, seat tube and all, clean everything, lube the seat rails, and the seat collar. Usually one of these steps will fix a "clicking."