Answer by Jacob Nelson:
The best way to learn CSS3 is to start with simple CSS. Then move on to CSS2 and then CSS3.
ie; start from the basics. Infact, This is applicable to any language.
Here is the complete list of CSS properties
Here is another list, which lists all the CSS selectors.
Understanding CSS selectors is very important, when we learn CSS.
Here are some nice tutorials which will help you to learn CSS quickly.