If you ever have a really important show, tip the sound guy before the show and they will take much better care of you!

This is obviously not some unknown earth shattering revelation, but it may be something that is overlooked.  Many working sound professionals have 5 bands thrown at them per show in a club setting; many more in a festival setting.

The band that shows up with even a $20 and some kind words and appreciation for taking care of them will put that group right to the top of the priority list.  You may also find yourself getting more time to set up, more attention to detail, and maybe even a longer set.

On the flip side of making the sound guy happy, be sure not to piss him off before your set.  This is a relative stranger that will be part of the band that night.  At a minimum, introduce yourself before you unveil your list of demands.  Having an apathetic engineer is going to get your sound the bare absolute minimum of calories burned required to get through the set.

Hopefully this will help a few bands and sound engineers out there to get along just a little bit better.