Digital Footprint
Everything you do leaves a mark bad or good
Don't post anything that you wouldn't want your grandma to see.
I call this the grandma rule. Every time before you post imagine that you are asking your grandma if she approves if she wouldn't don't post it.
Friend requests
Never accept random friend requests.
Passwords
Never tell anyone (except your parents) your password.
Personal Details
Never tell anyone your personal details.