I came across this great article by Paul Williams on the Adobe Blogs. It goes into detail describing quite a few different Presentation Design Patterns for use in Flex (could be used in Flash as well).

Design Patterns, for those who don’t know, are general reusable solutions to commonly occurring problems(Wikipedia). They are a key component of Object Oriented Programming, and is not Actionscript-specific.

The patterns explained (with nice examples and source files) in the article are:

• Autonomous View
• Supervising Presenter
• Presentation Model
• View Helper
• Code Behind
• Passive View

Read through the article, and if you get stuck, drop a comment here and I will try to help out. You will not be disappointed, design patterns are probably your most precious ally when it comes to development.