1. Don't scrimp on your portfolio
No matter how busy you think you are, you should always find time to create a bespoke online portfolio. By all means, use sites such as Facebook, Flickr and Behance to showcase your work, but never use them as your primary portfolio. Using a social network in this way won't impress potential employers or clients.
2. Don't tell mates your rates
Never post your fees on a social network. While it's fine to discuss them with friends in private, an open forum isn't the place for such exchanges, as iPhone developer Mike Lee discovered when he revealed he charged $1,000 for an hour's work.
3. Go private
Don't rely on one Facebook account, and make a distinction between personal and private pages. If you have a Facebook identity, engage with people who want to discuss your work via a fan link, and don't accept friend requests for your private account from people you don't know (use the 'Have I had a beer with you?' rule).
4. Quit copying
There's nothing social network users love more than exposing plagiaristic activity when they spot it, so don't copy other people's work. This may seem like a no-brainer, but many designers are often tempted to cut and paste.
5. Don't be a bore
Nobody wants to listen to someone moaning about every new design they've come across. If you do feel the need to critique someone's work, be constructive. Comments along the lines of, "This sucks!" and, "Are you a blind ferret?!" won't endear you to anyone.
6. Play nice
Don't get engaged in public mud-slinging. It's often difficult to take the higher ground, but when you start being nasty online, things can get out of hand very quickly. This point was perfectly illustrated by director Nicholaus Goossen when he felt compelled to defend one of his films: www.vimeo.com/12855619.
7. Pick your personality
Don't join Twitter without thinking the commitment through. If you have a clearly defined brand then you may want to create both a personal and professional persona. For many, though, your personality is your brand. Just make sure you decide which approach to use before getting started - it's harder to make the separation later on.
8. Keep it clean(ish)
Don't fucking swear! Or do. For most of us, a bit of profanity is part of everyday life, but you must remember that not everyone reacts to it in the same way. Make sure that you know your potential client and customer base, and predict what kind of language they'll probably expect from you. Then be consistent.
9. Never bad-mouth clients
This is the golden rule. If you become known as a difficult designer, it takes a lot of time and talent to shed that reputation. And remember, most of your comments will be archived for future clients to read, so there's no going back.
10. It's not all about you
Don't just view social media as a new way to publish your work and increase your profile. Of course, you should publicise your creations, but it's important to build quality relationships with your peers, too. It's good fun, and if they feel they know you, they're far more likely to recommend you to others.