1. It's good idea when you develop some application with jQuery to use cheat sheet.
On the net you could find cheat sheets for jQuery. Here are listed some cheat sheets for jQuery:
Here is an example for loading of jQuery from Google:
3. Keep DOM manipulation to a minimum
4. IDs instead of classes wherever possible
jQuery makes selecting DOM elements using classes as easy as selecting elements by ID used to be, so it's tempting to use classes much more liberally than before. It's still much better to select by ID though because jQuery uses the browser's native method (getElementByID) to do this and doesn't have to do any of it's own DOM traversal, which is much faster.