I'm a bit of a social media "junkie," and wanted to give you some ideas for maximizing your online presence.
First off, your personal Facebook profile is where you're likely to get most of your initial business. After all, these are your friends and family, and maybe former colleagues, neighbors, etc. (depending on your personal policy about accepting friend requests andyour privacy settings). But sharing job search-related tips on your personal profile (as well as talking about projects you're working on for clients) can be a good way to spark some referrals. (I average a couple referrals a month from my Facebook friends...from my personal profile!)
The next step is to set up your Facebook Business Page for your resume writing business. It can be tricky to get your business page Profile picture and Timeline cover graphic to look just right, but you can find someone to help you on a site like Fiverr.com (and it's just $5). You'll find that it takes time to build your "Likes" to your Business Page (most resume writers average around 75 "likes" for their page -- but there are many with as few as 5 "Likes" and a few with 100+). While "quantity" is your eventual goal, quality is a great way to start. Share tips and ideas, link to interesting articles (don't just post the link -- comment on it!), and share your client success stories (not by NAME specifically unless your client says it's ok -- more like: "Just got a call from Ann K. who received three calls for interviews within 2 days of sending out her new resume. Nice!"
On the subject of getting the most out of your social media presence, there's Twitter. As I remarked to a colleague today: You either love Twitter, or you don't understand it. A lot of people set up Twitter profiles and don't do anything with it. The key with Twitter is: The more you do on Twitter, the more you'll get out of it. I admit, it has kind of a steep learning curve to begin with. There's the whole follower thing (i.e., you can Tweet at anyone with an unprotected Twitter account, but you can only get Direct Messages from someone you're also following) ... there's "Twitter-etiquette" -- like acknowledging retweets (RTs) and mentions (MTs), the phenomenon of #FollowFriday (and the whole explanation of hashtags #) and how/when to use them ... and, of course, how to manage the Twitter stream (as it relates to time management).
The easiest thing to do with Twitter is to set up your Twitter account to interface with your Facebook Business Page (it's quite easy, actually) and have everything you post to your Facebook Business Page automatically post to Twitter. Also, check in for 10-15 minutes a week on Twitter to respond to Tweets and DMs, follow people who are following you, etc. You can also set it so that Twitter automatically posts to your LinkedIn account.
You can learn more about how to use social media for client acquisition in my "Introduction to Social Media for Your Resume Writing Business" special report, available to Bronze members on BeAResumeWriter.com this month (June 2012).