Formatting for CreateSpace

I’ve went through two versions of my book in CreateSpace and have been displeased with the format so I need your help.

What font, margins and other tweaks do you recommend for a 6x9 book to make it look professional?

I’d really recommend using Word or similar for these final stages. There ought to be a good template for this you can find that you can use to squeeze the Scrivener compiled output into. A good word processor will let you auto-format, or select broad ranges of text using the same format, making it easy to conform it to the template stylesheet. For novels this may only require two moves, one for chapter titles and another for body text.