I redesigned my personal site a little over two months ago. In that short time, traffic to my site increases by 50% each month! I regularly contribute to web development forums with my URL in my signature, added to each post. I can see from my stats that users do click through to visit me. My suggestion is that whatever industry you're involved in, find a forum tailored to it and contribute. Show everybody you know what you're talking about and they'll seek you out as an expert on that topic.
Additionally, I installed
WordPress, personal publishing software for my web site (a blog). On a regular basis, I write about something that I'm working on professionally. I'm a little new to it but I think WordPress automatically submits new articles to blog directories for inclusion. All I know is that last week I wrote about a program I was working on to automatically create sitemaps and submit them to Google's sitemap service and in less than 24 hours after publishing it, I got an email from someone who found my site inquiring about my program. You can't beat that.
Those are my best suggestions for increasing traffic to your site without paid advertising.
-Mike
