This Adobe After Effects tutorial will teach you some basic stuff on what you can do with expressions. It's a fancy or flashy effect what you will learn, but you will learn the key to one of the most powerful tools in After Effects.
This tutorial is given by Jordy Vandeput form Yapper Design. Check out the website for more free stuff on video editing and tools.
This Adobe After Effects tutorial will teach you how to create a folly customized smoke effect with only standard effect from the library. Instead of using pre-filmed smoke clips which you can blend in your videos, you can make it yourself. Change the path, the smoke type, color, etc.
More tutorials and free tools for media design: YapperDesign.com