Writing keyword rich articles and article submission. There are a multitude of article submission directories out there but my preference is EZA. It's PR6 and I get good traffic from it. Also, social bookmarking sites. Again there are loads of them in the net. Just Google them.
SEO is what I do. I used to do other type of advertising, but now only focus on creating content on my site. Traffic has double, bounce rate went down, average stay time went up, google ranking went up, and so google visits doubled. The sad thing is adsense revenue went down, but it is getting better this month.