Some search engines consider site popularity as a criterion for how high up in the listing you should be displayed. Because of this, services offering link spamming are available. I don't recommend link spamming. Put your URL on any non-web promotional pieces that you do. If you regularly use direct mail, be sure to include your web address.
Many people hear about a site initially via non-internet channels.
Make your present customers aware of your web site. Notice that the easier your web domain name is to remember, the more likely it will be remembered. Short catchy phrases are best. It is well known that to keep people coming back to your web site, you want good content and links to other great sites. One way to get this is to encourage others to contribute to your site.