Tips on Promoting Home Based Businesses

There are endless networking websites available for promoting your business. I represent a construction safety product which has a pretty specific consumer base...facilities managers, carpenters, etc...people who install heavy, over sized doors. We work from home and are currently on Twitter, Facebook and HBB.com. If anyone has any tips, additional free networking sites (Home Based Business is awesome by the way), or input you could share with me, it would be very appreciated...I've attached our product brochure, just to help you get a better idea of our product. Thanks for the help!