There are lots of techniques like social n/w profiling,social bookmarking,social signal and social media marketing which helps to promote our business site through Facebook and other social media sites also.
Sharing posts that attract users like share discounts, offers and new attractive ideas. This kind of post help to get more and more visits. Join or like other pages that are same as yours.
Creating a Facebook fan page is important for marketing your business after that integrate with blogs other social networks and groups(Do it naturally).
Include more numbers of friends in your Facebook account, share post related to products, get comments and like on that, this will help one to market on facebook.
Effective use of Facebook Groups is great way on Facebook. Using Facebook Groups gives you the opportunity to target a specific market. Compared to other advertising channels, advertising on Facebook is not only effective but cost effective.
The problem is most people do Facebook Groups advertising the wrong way..Telling people to join your business or to buy products and service from a Group is not effective
Here is what I would do...I would post a FREE REPORT on the groups to flex my knowledge.."7 Ways To Be More Productive" 5 Ways To Drive FREE Traffic To Your Website" you get the idea...
By doing this you stand out from the crowd and people will take note of you...