June 05, 2007 Google’s PageRank Revealed 
A thorough dissection of everything known about Google’s PageRank methodology at Smashing Magazine highlights just how important optimal HTML development is. Every little thing overlooked or done right can lower or boost your score.
From the article:
Headers (h1, … ,h6), strong tags and semantic content are important. (Update: But it doesn’t improve PageRank.) “Place it in the description and meta tags, place it in bold/strong tags, but keep your content readable and useful. Be aware of the text surrounding your keywords, search engines will become more semantic in the coming years so context is important.”
At the heart of solid HTML development is semantic markup used intelligently. There are no hard and fast rules here. There’s no piece of software that reads your copy or looks at your design and says “that’s an H1 (the biggest) header.” It’s a matter of relying on a developer who cares that everything makes sense and is coded appropriately.
Efficient internal onsite linking is important. “Internal linking is important to your overall ranking. Make sure your linking structure is easy for the spiders to crawl. Most suggest a simple hierarchy with links no more than three clicks away from your home/index page. Creating traffic modes or clusters of related links within a section on your site has proven very effective.”
Again, the right developer will carefully consider how to name your pages, how to construct navigation elements and links, and make recommendations to optimize your site’s navigation not just for the user, but also the search engine.
Anchor text is important. The more specific is the reference, the better Google can evaluate it and consider it in relates search queries.
“The anchor text of a link is often far more important than whether it’s on a high PageRank page.”
Write smart copy. Don’t use links that say “click here.”
Links from and to high quality related sites are important. “The more closely related the pages, the higher the PageRank amount transferred.” “Linking to high quality sites shows the search engines your site is very useful to your visitors. Unless your site has been around for years and is well established and trusted by Google, this factor will have an adverse effect on your site’s overall ranking. Linking only to high quality content sites will give your site an edge over your competition.”
Incoming Links from popular sites are important. If pages linking to you have a high PageRank then your page gains some part of their reputation.
The more content you have that others find valuable, the more inbound links you’ll get. The more inbound links you have, from popular or related sites, the better you’ll fare.
