Affiliate systems are one of the best ways of increasing sales on you online store. They are systems that track "referrals' to your e-commerce website from other sites, and reward the sites that send you customers by giving them a percentage of the sales profit. IF you have great products, these systems have the potential to increase your sales many many times over.
Examples are http://www.linkshare.com
If you don't have an affiliate program for your business, set one up today, and start getting other sites working for you.