All the web (FAST) Guidelines

• Make pages for users, not for robots.
  
• Place important visual content on top-left fold of the page (640 x 480).
  
• Use a large logo if possible.
  
• Place useful images that accurately describe your content. Show big colorful pictures of flowers if you are a florist. Show mathematic graphs if you are a statistics site.
  
• Place useful text information that describes your content. A news web site may want to emphasize text over images. A photography site may want to emphasize graphics over text.
  
• Use friendly colors, not excessive "burning" colors.
  
• Use colors that represent your content. Warm colors for florists. Strong colors for game sites.
  
• Use consistent color and layout across your site. Humans recall better when they see the same look and feel.
  
• Avoid making drastic layout or color changes too frequently.

• Each picture should not exceed 80kB in size.
  
• DHTML content generated using Javascript must complete in less than 5 seconds after page is loaded.
  
• Use <object> tag for Flash media because <embed> tag is ignored.
  
• Flash object should complete animation within 10 seconds after loading.
  
• Flash file size should be under 500kB.
  
• Meta-refresh, Javascript or Flash redirects must refresh page in under 5 seconds.
  
• Use ALT tag to provide text information for your images.
  
• Enable support for the If-Modified-Since and ETag HTTP header. These features tell robots whether your content has changed since it was last visited.
  
• Don't deceive your users, or present different content to robots than you display to users.