A couple quick tips…
Found this HTML5 Element Flowchart by HTML 5 Doctor and wanted to share the link. I think it’ll come in very handy when making choices with HTML5. This chart has a basic flow chart for determining which HTML5 Element (<nav>, <article>, <section>, <aside>, <section>, <figure>, …) to use and when.
Next, I think this tool written by Adnan Topal will come in handy for cleaning up HTML with inline styles, especially projects where developers did not follow best practices for styling, themes and using CSS style sheets.