Pro tip: I used to think the old way of tracing a short was fine until a guy at the hangar in Mesa showed me something better.
I was stuck on a phantom power drain on a King Air for two days, pulling panels and checking every wire. This old guy, Frank, who works on the warbirds down the line, walked over and just said, 'Stop looking with your eyes, kid. Hook your meter up to the main bus and watch the voltage drop while you pull fuses, one by one.' We did it right there on the tarmac, and in about ten minutes we found it was a bad landing light relay. I've done it that way ever since. Has anyone else got a better trick for finding those sneaky drains?