Some things can hardly be learnt through the mere use of words. For a start, search the web for some pointers on how to go about. I'm sure you'll be able to find quite a lot of useful material if you Google.
1 single flash wont do the job that well unless ur damn good at setting up lighting thru use of reflectors and so on. Use a white backdrop. Some people have a dedicated light that shine on the white backdrop to eliminate the shadows.
Another important thing is pose. Go look through corporate reports and u will see what angle is "standard" and "expected".