Professional site construction

Hi, as you see I’m new to the forum and after I explain my situation I have a couple of questions. Answering any of those questions would be very helpful to me. OK, so this is my situation…
I’ve worked SwishMax for several years and got to the point where I understood that the software itself is limited, even with new SwishMax2 (for example no class support). It took me several years, but now I believe that there is no need to wait for something that is already invented, in this case - Flash. My work is based on design and building full flash sites.
As I’ve decided to try start working with Flash, I’d be grateful for some guidance regarding building websites. As SwishMax and Flash are somehow similar but on the other hand different, here are the basics I’d like to know so I can get started.
How is a professional website constructed(I understand that I’m trying to hit high, but one of my idols is Miro from DrawingArt and that kind of quality is what I’m trying to achieve)?
What is the best way to load external data (XML/database)?
What do I gain (or do I?) with using CSS in my Flash movie?
These are some of the things that would help me a lot…for now :slight_smile:
Anyone who can answer any of this questions?