Cadalyst magazine has several newsletters. I am the Tip Patroller for their weekly newsletter Tips & Tools Weekly. It is published every Monday. This weeks tips include:
Start Commands with a Double Click
Set Extrusion Distance
Program Keyboard and Mouse Inputs
Go to Cadalyst's website and click on the CAD Tips button to find all of the tips and to sign up for the newsletter. Every tip is reader submitted. There is a ton of great stuff there.