To find a short, first disconnect the obvious devices (eg. taillights if blowing taillight fuse) to see if fuse still blows. Also try disconnecting everything that is or may be on that fuse’s circuit or anything suspicious or recently worked on that’s electrical. Disconnect anything electrical that doesn’t work. Examine the wiring and connectors on the things you disconnect to see if they are frayed, broken, melted, wet, or touching other wires or metal. 95% of the time you will find the short this way (which is also the quickest). If you have very weird symptoms (eg. headlights never go off, or turning on one thing causes something else to happen that shouldn’t), try unbolting the engine fuse box and examine the cluster of wires underneath. Some may be melted, broken, or shorting against others.

If it still blows you will have to use a tougher technique. Replace the fuse that blows (temporarily and only for testing purposes) with an actual small 12 volt light bulb like a automotive tester light, marker light, or license plate light (don't try to start the engine with it in). The bulb will limit the current so you now don’t have to worry about any short melting the wires. If you don’t have a tester light you may have to solder wires on a bulb or put a bulb in a socket with wires. Then insert the wires into the slots where the fuse was. If there is a short, it will lite brightly (no short may lite it half bright along with a device doing the other half, or it may not lite at all). Then start disconnecting one at a time (1) things that don’t work, (2) suspected things, and (3) anything on that circuit. When you disconnect the item that is causing the short, the light will go out (so it's a great detection device). Keep in mind the short may be in the wiring or fuse box which is harder to find, but first check all the easier, more obvious devices and places.

Here is also a helpful link: http://www.dsmtuners.com/forums/showthread.php?s=&threadid=54846