Anybody have any interesting troubleshooting methods for saving time? The tips could be for anything from a complete system failure to an individual device.

Although this is common and probably used by everybody, I'll start the conversation with my method for a shorted out series of lights (say, and outdoor series with underground feeders)...

A. Look for physical damage or any other obvious causes along the length of the run, including damage or water intrusion to fixtures.

B. Isolate and reconnect: Isolate half of the fixtures on the run and reconnect each half. When the breaker pops, continue to isolate sections of the shorted run until you narrow it to either the bad fixture or the bad underground run.

C. Rinse, repeat.