I use on-page SEO. Basically, I keep in mind the terms, synonyms, and phrases people tend to use when talking about my topic. I'm not chasing popular searches; rather, I try to be specific enough in my writing that search engines understand what I'm talking about so that they'll send me exactly the people who will be interested in my webpages.
I also set up Google authorship so that when my hubs appear in search results, they look appealing (my profile photo is a professional portrait -- it's silly, but good images tend to attract clicks.)
Most of all, I try to create useful and engaging content, drawing on subjects I know well and looking for ways to convert what I know into interesting or helpful pages. It's the hardest and most effective way to get traffic: create fascinating or useful content that people like so much that they're likely to share it.