Don't put anything on the internet you don't want people in your real life knowing about you.
Don't post anything that could get spread like wildfire over various social sites.
Don't post personal things that people can and will bash...because if you get offended, or hurt...I don't care what you posted, you posted it for anyone to see and have a comment on, that bit is on you.
Rules of the internet are simple....if you don't like it...don't log on. Some people are nice, but most are nasty bitches.