A simple trick to finding a short is to replace the blown fuse with a pair of spade terminals, then use small jumper wires to connect them to a 12 volt light bulb. A brake light bulb works well. When the circuit is live and the short is present, the bulb will be full brightness and hot so be sure it's not laying on the carpet or against a plastic door panel. Now you can unplug electrical connectors and move things around to see what makes the short go away. When it does, the bulb will get dim or go out.
In the case of the ASD relay, it only turns on for one second after turning on the ignition switch, (not nearly enough time to do any troubleshooting), and during engine cranking, (not real convenient). Instead, use a stretched-out paper clip to by pass the relay while you're diagnosing the short. In particular, check the wiring to the oxygen sensors to see if it fell down onto hot exhaust parts.