We use a piece of rubber hose or tubing with one end moving around the engine, the other to our ear. Listen for ticks or whatever under the valve cover. Others use a dowel or broom handle. You will hear things as there is a lot going on under there.
Another thing I did to get a better handle on any problems was to cut an old inline valve cover so the sides were still there but the top was cut out. I could watch the whole operation with the motor running and not get oil everywhere.

Six volt guy living in a twelve volt world