People do what other people do.
So, if people are buying from you, let other people know.
A great way to do this is to have software installed on your website like ProveSource.
My conversions have increased DRAMATICALLY since having this on my website.
UseProof claims that website owners get up 300% more conversions.
I can vouch for that.
PS. Set it up once and let it do the selling for you 24/7.