Back during the time of FE beta there was a post template for bug reporting, with a forum section for that. Basically you make a post with a standardized title that identifies it clearly as a bug report for version x. You write a description on how the bug happened and include save game and that`s it.
I expect there will be the same once the GalCiv III alpha is out. Reporting bugs or problems in the most formalized and concise manner makes their job easier and is probably one of the greatest service we can do for them as Founders/testers.
Beside that, feedback is also very important but I believe that feedback kept in a short, clear and specific manner is the most useful. ( Brad`s prototype feedback PDF in the founder`s vault is a good exemple ). Long and convoluted walls of text are going to be harder for Stardock to sort through.