The Rocket-Science of being a polite band:
1) Good contact beforehand (who's going to bring the backline, terms of payment, backstage area if you are big enough)
2) Good contact whilst being there (hey wzp, we're here... everything okay? who's stagemanager, who's soundtech if you're not bringing your own)
3) Good contact after being there (thx, well organised (if it was) nice venue)
its easy