Some jQuery tips.

gistfile1.js

// Always use lates version

// Not all selectors are equaly fast
// Fastest to slowest selectors.
$('#selector-by-id');
$('div', 'input');
$('.class-selectors');
// And the slowest are pseudo selectors
$(':visible, :hidden, [attribute=value]');

// Efficient selectors
$('#wrapper').find('.first'); // Better
$('#wrapper .content .main article.first');

// Use caching! 
var $firstArticle = $('#wrapper').find('.first');
// But avoid using global variables by using immediate function or similar.

// Use chaining
$firstArticle
  .fadeIn()
  .addClass('active')
  .css({				// Also, use object notation for adding multiple css rules
		paddingLeft: '20px', 	// instead of chaining .css() multiple times.
		marginLeft: '20px'
	});

// Attaching data
$('#node').data(key, value); // Slower, creates jQuery object
$.data('#node', key, value); // Faster