Steve Souders in his website has given 15 tips - some very fundamental ones for creating high performance websites, along with demonstrations of what he says. Very Interesting and useful.
The list is here. Visit his website to actually see the demos.
• Rule 1 - Make Fewer HTTP Requests
• Rule 2 - Use a Content Delivery Network
• Rule 3 - Add an Expires Header
• Rule 4 - Gzip Components
• Rule 5 - Put Stylesheets at the Top
• Rule 6 - Put Scripts at the Bottom
• Rule 7 - Avoid CSS Expressions
• Rule 9 - Reduce DNS Lookups
• Rule 11 - Avoid Redirects
• Rule 12 - Remove Duplicate Scripts
• Rule 13 - Configure ETags
• Rule 14 - Make AJAX Cacheable
• Rule 15 - Use Iframes Wisely
He even talks about tools that he has used for some of these tasks, ex. JSmin to minify a script, Dojo compressor to obfuscate a script, etc.
Interestingly he also points that most of the optimization for better performing websites seems to be a front end problem more than a back end one. He has learnt this when he was the chief performance Yahoo! and has published a book "High Performance Web Sites: Essential Knowledge for Front-End Engineers " on the same.