So, i was thinking it would be kind of cool to start a thread not about playing guitar, but being in a band. Share and take advice from this thread. Add your own advice. I'm interested in hearing from everyone.
Here's some of my own...

*Learn how to take criticism and orders without getting all huffy
*Learn how to give orders
*Don't fiddle around on your instrument when others are talking
*Be honest when they ask if you like what they are playing
*Don't shoot down riffs people present right away. Remember that they spent time writing them, and are probably kind of nervous to show you. You may even eventually grow to like the riff
*Show up for band practice
*Create goals so you don't waste time

I've got more, but let's hear what everyone else has to say about this...