Hi, I have two Facebook fan-pages. One of them is taking a life of its own and growing every week. I followed two of the many pieces of advice found at Social Media Insider.
1- I got the app Fan of the Week. People seem to like being picked by that app and they participate and "like" the page more because of it.
2- I let them "show and tell" with my products on my Facebook fan-page.
If you sell a product that is tangible, let's for the sake of an example, electronics, ask your fans to take a picture of themselves with the product that they bought from you and posted on your fan page. Do the same on your blog and dedicate a whole Pinterest Board to fans. You will not believe how many people want to be featured!
As I said, I got those ideas from Social Media Insider and they have worked for me, together with elbow grease, good posts, great products and God's blessing.