(my first post here, so I'll try to make it count)
I make a decent living from selling products on the Web. I've enlisted a legion of both affiliates and drop ship buyers (I drop ship the products to their customers) to help grow my business.
There are several things I've learned, which I hope will help you:
A) Be patient: My business is two years old, but I almost sold it to a relative about 16 months ago for a few hundred dollars. That would have been a tragic mistake, because the business now makes a six-figure profit each year. Know that it is likely to take at least 2-3 months to get any significant activity and sales volume, and 6-12 months to really have things rolling. In addition to my main sales site, I've opened additional sites/businesses, and that timeline still seems to hold.
B) Be active: Don't create a sales site and let it sit. I found that if I doubled my product offerings, I doubled my sales. Obviously, there is some point of diminishing returns, but keep growing until it is clear.
C) Try various avenues: Join an affiliate program as a merchant; offer drop shipping; offer wholesale discounts; offer products for sweepstakes to build interest; offer a low-cost (to you) free product if they pay shipping (obviously, the cost of the product should be less than your shipping charge); use low-cost services such as PRWeb to make announcements; and any other things you can think of that won't cost much to try.
For those of you trying to find "niche" markets to break into, here's my tip:
Someone mentioned earlier that the business-to-business arena is still going strong, and growing. I have found that in the wholesale products area in general there are very few competent players with Web sites. It seems that the manufacturers and importers simply aren't very good at putting together good, usable sites for their wholesale buyers (I don't mean sites offering "wholesale prices", but true to-the-trade-only wholesale distributors).