Create a warm and fuzzy place. Social media is the best place to get personal, just not too personal. Do you or your staff have an interesting hobby? or have you achieved an interesting personal goal like completing a marathon or further education? Clients want to relate to people, not titles.
Admit when you screw up. It happens. Own it, fix it and move on.
Mingle but don't get OCD. Yes it is a good idea to respond to posts and tweets but you can't insert yourself into every conversation, nor should you. If the same comment is being made, no need to add your two cents. As far as tweets Friedman claims three per day is the sweet spot, and don't forget to thank people for the retweets, it's just good manners.
Don't argue with your guests. Should a visitor on your page decide to air a complaint to post a negative comment make sure you act and not react. You can also take the time to see if some of your supporters will come to your cyber rescue. People after all just want to be heard, and sometimes they just might be right. Don't ignore the opportunity to learn from feedback.
LInked in has an entire list of do's and don'ts you can check out on their site like,
Will anyone care about this content besides me? Will I offend anyone and if so does it matter? Did I spell check? Big pet peeve of mine. Will I be OK with everyone seeing this? Is this an emotional dump, better stated in another outlet? Check out linked in for the rest of their recommendations. Anyone of these errors can cost you a client, and last I checked I need every last one of mine. So market smart and play nice.