Need Performance Improvement Tips for JavaScript / jQuery / CSS and HTML5

Need Performance Improvement Tips for JavaScript / jQuery / CSS and HTML5

Hello,

Could you please share your experiences for improving performance for web site developed using
jQuery
JavaScript
CSS and 
HTML

I got some good post regarding performance online but I am looking for some tips and tricks I can use in my regular development. like which event handler technique to be used, which CSS properties are costly, what should be avoided while using jQuery/JavaScript..

thanks,
KK