Place ads in papers or trade journals targeting your audience. Write a column for a local newspaper. Offer a free Web seminar at a library. Go where your customers go. Provide a form or an email address so customers can include comments.
Web statistics can provide important information.
You may be getting a lot of visitors, but very few orders. Look at your site from a customer perspective and review the tips about Web design. Even angry letters can serve a purpose. Check your graphics and your Web server. Maybe it's time to expand the product base.