After Effects Expression Debugging Techniques

Felt Tips at AE Tuts+ has a fantastic, in depth 50 minute tutorial on fixing issues with Expressions.

Check out the Tuts+ websites for more great tutorials.

Looking for more on Expressions?

• MamoWorld iExpressions – Contains over 100 iExpressions – and each of them comes with an easy and intuitive to use interface.
• MamoWorld ExpressionTimeline – The ExpressionTimeline allows you to apply several expressions to a property such that each expression is active only for a certain period of time. Instead of an abrupt change between the expressions you can also smoothly transition from one expression to the next. Furthermore, you can specify time intervals in which no expression is active such that the keyframed motion is considered.