1) Don't be a jerk
Respect me and my friends and family.
2) Text back
I know you may be busy, but its polite to say, hey I'm busy, text me later. Then not saying anything at all and leaving me feeling worried.
3) Don't cheat
It is tempting, but it isn't morally right, and it leaves the other person feeling like crap.
4) Don't pressure me to do things I don't want to do
Just don't do it.
5) Just be a nice person
It makes people smile :-).