We get a lot of customers through SEO as well. Start with the easy stuff like a) creating keyword-laden browser titles for all your pages, b) having good text

We get a lot of customers through SEO as well. Start with the easy stuff like a) creating keyword-laden browser titles for all your pages, b) having good text content in your pages (especially stuff like your "about" page(s), c) linking to your site from any other web properties you own (personal blog, etc.), d) make sure the links have good anchor text, and e) blogging. When you blog, take time to write good content–and make sure your post titles have keywords in them (keywords in header tags help). You might consider an SEOmoz subscription just for a month or two. Go through all their articles and you'll learn a lot.