You have a good basic understanding.
What now?
1) Work on the interface-reference current design trends and other "quality" flash sites, check out flashkit's tutorial and fla section, refine.
2) Make the site Gel, maybe choosing a color theme and template scheme, Use a vector based app to create a front face look and then export to flash.
3) get rid of all pop-ups
4) lose the borders
5) Purchase a few books on flash design techniques.
6) Work on content

Good start.