Pay attention, this is going to be good. That's it, really. If you pay attention; to where you are, who you're with, and what you're doing; things will be good for you and the people around you.
If you are with one person, or group of people, it's rude to stay on your phone (talking, texting or checking FB) for extended periods of time. Enjoy the people you are with and have conversations with your other friends when you're alone.
I have noticed that cell phone and texting tips are rarely discussed and that people have to learn the "rules' all on their own. I'd like to share a little of what I have picked up.