For Angularjs and the MEAN Stack
There is a great set of tutorials for Angularjs on code school here. I used them to learn the basics but in reality the best way to learn is to build a project you're passionate about.
For myself I learned how to use Ionic for mobile development, here is my open source code for that (Ionic is built on Angularjs).
Another great way to learn is to follow the Microsoft MEAN Stack video that they made about 6 months ago here it is. They do a full MEAN Stack project thats really easy to follow along with.
To learn any new tech build build build, its the only way to discover more. Good luck