First, make sure your prospects are using social media in the first place. (Not everybody does. It all depends on who your target audience is.)
Second, find out which site(s) they use most frequently. If all your prospects are on LinkedIn, it won't do you much good to be on Twitter, and vice versa.
If you don't know whether they use social media, or you don't know which sites they frequent, you need to do a lot more audience research -- because I'd be willing to bet there's a lot more
about your prospects you don't know, either.
Once you've figured out where your audience is, spend a little bit of time lurking if you're not already familiar with the community standards of those sites. Things that would go over great on Facebook might not be so well accepted on LinkedIn, for instance. If you want to be successful with social media, you don't want to annoy the other people who visit that social media site.
Then, start connecting and posting. Post interesting stuff. Be generous with promoting/passing along other people's stuff -- don't just blahblahblah about yourself and your company and your products. That's boring and isn't going to win you any friends. It's OK to talk about yourself and your company, just don't let it be the only
thing you talk about.
And don't just talk. Listen, too. If someone addresses a message to you (public or private), answer as soon as you can. Talk back to others when they say something interesting. Social media is supposed to be a conversation, not a broadcast.
less taxes, adjusted for inflation.