I have Facebook, LinkedIn, and Twitter accounts and I am constantly working to keep them fresh on a regular basis. My time is precious so I tend to spend no more than 20 minutes on any social media, catching up with people I am connected to and posting something relevant to those who follow me. Social media puts a more personal touch to having a business, it shows others what you and your business are about.
Facebook gives you a private and business page, consider keeping the "very personal stuff" out of sight on your personal page if you want your small business to look professional. Potential Collectors read both your personal and business pages to find out more about you. Use social media to direct potential buyers to events and news about your art business.
If you are new to using social media then choose just one to start, you can always add more later if you feel you need to. Your best asset is your blog if you have one. I find the three social networks I am using can be connected to each other, keeping it easy by sharing my single post across all three. Ask yourself these questions: What Social Media site are my ideal followers-fans most likely to be using? Who do I want my followers-fans to be?
Greet anyone new who has followed you.
Respond to comments / posts on your page/ mentions / direct messages you have received
Follow people you feel could be of interest to your own followers
Follow new people that you think might match your ideal follower profile
Only post something of your own if you think it is going to be found either interesting, educational or amusing to your followers
Spend the rest of the time checking what others are posting; reply to any posts you feel interested in and re-post what you think would be of interest to your customer profile