Sergei Sokolov wrote article about Using automated tools across the lifecycle to develop higher quality Flex applications.
He explained some tools and approaches how to build better Flex based software.
I’d like to add some of my notes to this topic:
1. The key factor for reaching good quality of Flex products is learning. Flex is platform and it is evolving. Therefore it is imperative to learn new approaches to solve some problems.
2. Automation is very important. Flash Builder is bundled with support for Ant. That is not enough. Continuous integration should be implemented via tools like Maven using FlexMojos. Without this point everything is useless, because you’ll end up with mixing different versions of Flex SDK with your framework. Thanks to Jenkins and FlexMojos you reach stability in SW production. We already launched Jenkins CI for open source ActionScript projects – you can find some details at corlan.org.
Here is small example how to use FlexMojos.
3. Teach developers how to use FlexUnit. Companies tend to buy cheaper version of Flash Builder which has no support for FlexUnit. Investing few more bucks could give them very handy tool. See lynda.com or tv.adobe.com for lecture about FlexUnit. There are also other helpful tools like FlexMonkey, etc.
4. Different tools. Flash Builder is great, but real development power comes with combination of Flash Builder with IntelliJ Idea Ultimate. Those two tools together could speed up development and improve code quality. Also test automation has good implementation in IntelliJ Idea.
5. Flex PMD. This could help team which deals with new developers. Often it is hard to guess level of skill of new developer in the team. Using Flex PMD could help with measuring and detecting anomalies in his code style
6. Get rid of Not Invented Here Syndrome. There are many small useful frameworks which could help to improve Flex productivity, like Swiz, RobotLegs. Knowing those frameworks could save hundreds of development hours. So give a space to developers to learn new approaches.
I prefer small frameworks with less singletons inside. Some Flex frameworks are overflowing with singletons. Do not use sw with too much singletons, it will bite you and maintainability of your Flex product will drop to zero. Just a friendly warning at the end 
In my opinion this is the core of producing real good and stable Flex software.
