Have you ever put together a small event and realised just how many cables there were going to and from the stage?
This is where you should consider using XLR snakes. They put all the cables into one, so it's the only one trailing between the band and mixing desk. It usually has a box for on stage, where the mic cables all get plugged in and the other end has the individual cables splitting up again to go into the mixer. Quite often they also have channels going the other way (XLRs are unidirectional, see here for more) and they are for the mixer outputs e.g to the P.A system and to the monitors.
These get quite expensive (>£100 usually) so you should weight out the benefits first, if you are just running two channels, it is not worth your time or money. They are also heavy and bulky however, setting up a gig tends to involve that anyway so it may not be an issue.
They really do help the tangle of wires that stages can become and following a wire is dead easy when there aren't 12 identical ones criss-crossing about.
If you have all the other equipment for a P.A system, this is a worthwhile investment. If you don't, you are probably better off with some electrical tape and giving yourself an extra hour to tape it all down neatly.