Replying to [Rizzob]: Many of the answers apply on the competition and price, however depending on the kind of product a company manufacture and sell is the differenciation that makes the big difference.
I believe that most of the companies loose customers because they cannot answer a very simple question - WHAT IS NEW?
Any company that want stay on the market and be competitive need not only care for its customers but also have constantly new thing, modify what they have and put up on the market in constantly different way.
If you pay attention on the biggest companies on the market you can see they are constantly changing the bottles and packages of their products, many times the product itself dont have anything different of really very little, but because the have updated their product sending to the market as new - everybody want to try and check on the "new" thing.
As small companies that dont have the same financial conditions that the big ones, we must keep up to contantly improve our products and find new ones to come up with even as accessories for the ones we have - this way we keep contact with our customers and give him or her a reason to constantly buy from us.