Pay Per Click campaigns are great, but I like to use SEO techniques to give my sites the best fighting chance of coming up high in 'organic' search results.
All the XHTML, CSS and PHP in my work is hand coded from scratch. My CSS is shorthand, and all images are optimised in Photoshop to ensure minimal loading time.
All the XHTML in my work is valid, you can see for yourself by clicking here!
My work conforms to W3C's accessibility guidelines.