David Pogue of Yahoo tech gives a great how-to on 13 settings you can change to make your iPhone less annoying. I do pretty much all of them:
"When you turn on Do Not Disturb (from the Control Center or Settings → Do Not Disturb, the phone remains quiet and dark. It doesn’t ring, chirp, vibrate, light up, or display messages. A moon symbol appears on the status bar to remind you why it seems to be so uncharacteristically depressed."