What are the best thumb rules for optimizing website via CSS?

The best thumb rules for optimizing the website via CSS are:

• Fewer Images
  • Use sprite image
  • Use font base CSS Icons
  • Use CSS styling text instead of graphic text image
• Organize CSS Code
  • Reduce unnecessary code
  • Shorter Class and ID Names
  • Document your code
• Less Usage CSS Hacks
• Put the CSS file on top
• Minimize CSS Code