This is my way of testing fuses both inside and outside of the fuse block.
I replaced my parking light fuse with a blown one, and showed how to perform the first step in troubleshooting electrical circuits with several testing tools from your basic 12v test light to the head ninja in charge of the 12v testing world, the power probe.
Standard 12v test light
Digital Multi Meter
This is for fuses only! Computer circuits need to be tested with a computer safe test light!
These tests can be done on a variety of fuses and applications, from the 10 amp mini fuse for the parking lamps to the 300A ANL fuse protecting a wire running to an amp.