CSS formatting:

Hello, I am trying to figure out how to modify a skin to make it visually appealing.  I created a duplicate of the styleshout-stylevantage skin and modified the colors, etc.  I have not modified the layout yet, but I am trying to figure out how to add some spacing to the right left or center so that when I put content in two of the sections they are not right on top of each other.  I currently have content on the right side and the center section.  I have tried adding more margin space to each but that does not seem to work.  Do i need to modify something else, maybe the page width?