A good way to start learning After Effects is by following tutorial videos. There are a couple of places that provide high quality video tutorials, in this article you can see a couple of them.
1) VideoCopilot.net – the undisputed champion when it comes to After Effects Tutorials
Andrew Kramer has a great teaching style, he combines a good sense of humor with advanced AE technique demonstrations.
2) ae.tutsplus.com – great amount of high quality tutorials
3) Motionworks.com.au – John Dickinson is doing an incredible work in providing easy to understand tutorials but also helps you understand how to work with clients. You can learn how to use Cinema 4d as well as After Effects from him.
4) Mattrunks.com – Here you will find some nice hidden gems, you may want to learn French (as I do) after seeing these tutorials
5) http://www.graymachine.com – Harry Frank has been creating video tutorials for many years, and his teaching style will help you understand quickly after effects and animation in general
5.5) The BlueFx Video Academy
Here you will get access to full After Effects courses including an entire course on how to edit After Effects templates, as well as monthly Live Classes, where you can participate and get your questions answered.
Other after effects tutorials recommendations
I also recommend the following sites for after effects tutorials:
Any other recommendations all well received