How to develop in Flash the RIGHT way?

[COLOR=black][FONT=Verdana](note: I guess this is actually more like a general Flash question, but since I just upgraded to Flash CS4 and AS3, I thought this would be the best place)[/FONT][/COLOR]
[COLOR=black][FONT=Verdana]Hi, even though this is my first post, I’m a pretty experienced programmer.[/FONT][/COLOR]
[COLOR=black][FONT=Verdana]I’m using different programming languages in my work but my hobby is Flash, and I made several games :)[/FONT][/COLOR]
[COLOR=black][FONT=Verdana]Anywho, I can get my stuff to work eventually, but everytime I start actionscripting I get this weird feeling - “this is [FONT=Verdana]not[/FONT] how it was actually meant to be done”.[/FONT][/COLOR]
[COLOR=black][FONT=Verdana]To be more specific - where the hell I’m supposed to code? In frame number 1? In a different file? In every frame?[/FONT][/COLOR]
[COLOR=black][FONT=Verdana]I used to even put code on my MovieClips but now in AS3 it’s impossible :P[/FONT][/COLOR]
[COLOR=black][FONT=Verdana]Also, programming in Flash itself is pretty annoying for me, not auto-completion or anything.[/FONT][/COLOR]
[COLOR=black][FONT=Verdana]I’m also interested in learning how to write my own classes and using them, which I just can’t understand.[/FONT][/COLOR]
[COLOR=black][FONT=Verdana]IN SHORT- I just wanna know how the pro’s do it. What’s your work process?[/FONT][/COLOR]
[COLOR=black][FONT=Verdana]I would really like to hear some advices and read articles if you link me to any.[/FONT][/COLOR]
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[COLOR=black][FONT=Verdana]Thanks dudes.[/FONT][/COLOR]