This is quick post from my note. It is a written in short and precise manner.
A) Content: Fewer Request, Reduce DNS lookups, Avoid Redundancy, Make Ajax Cacheable.
B) Server: Use CDN for parallel download, Add Cache-Control Header and Expiry Header. Gzip files, Add ETags, Avoid empty images. Though, new browsers can download 6 resources from a single hostname compared to earlier 2 resources. So, I think, for normal website and blogs with not so many images, using CDN for parallelizing is not that important.
C) Cookie: Reduce cookie size, use cookie free domain for static files.
D) CSS: Style at top, Avoid CSS expression, Choose link over @import, avoid filters.
E) JavaScript: Minify. Js at bottom, Remove duplicate script, Minimize DOM access.
F) Image: Optimize images, Use CSS sprite to combine media files, no Image scaling.
G) Mobile: keep component under 25Kb., pack component into a multipart docs. I do not agree with multipart document. It is like creating your page just for mobile. It is time of Responsive Website. Here is a discussion on what multipart document means.
Source: Yahoo! Performance Rules.
