Okay, this may be really basic, but for some of you it may just be what you were looking for. Here is the basic wiring diagram for a standard 3 pin XLR connector, used in audio for mics, playback machines, intercom, etc.
Cable designed for being cut into standard mic cables may have 2 pairs of wire and a shield around the outside, in that case pair the colors together and make sure they go to the same pin number on each end. The surrounding shield should be soldered to pin 1. Balanced audio cable designed for installs usually has a black, white, and ground wire. The uninsulated ground wire should go to pin 1, the red wire to pin 2, and the black wire to pin 3.
I hope this helps. Contact me if you have questions or comments. I will try to add more helpful diagrams and other useful tidbits if I know that others are benefiting. Thanks!