Need help changing width of Standard theme

I have searched through a lot of posts on the forum trying to find info about changing the width of the Standard theme. I’m not sure how different this is than changing the width on any other themes. I’d like to increase the main blog area by about 20 px, and the right column by about 20 px. Obviously this would include enlarging the wrapper as well.

Any thoughts on how to best do this in the CSS? I would appreciate any suggestions!