While HTML5 is expanding in definition to include any whizz-bang feature in the post rounded corner web era, implementing actual HTML5 in your web app can be confusing. It's a fast moving landscape that touches everything from traditional web apps to mobile.
Paul Irish, the Google Chrome dev relations guy who gave us the bulletproof syntax for @font-face, brings us his HTML5 Boilerplate a great tutorial/starting point for implementing a number of best practices in your desktop and mobile web applications including
<!doctype>and CSS reset
- Handheld stylesheets
- CSS media queries for advanced mobile device targeting (even portrait or landscape layouts)
- Paul’s Modernizr script for detecting device capabilities such as
The current version is heavily documented. Paul promises a more slim, production ready version soon.