How to have proper gaps between sidebar widgets

Hi,

On my blog addictmusic.co.uk I a have a lot of widgets in the sidebar that appeared stacked.

What I would like is for them to appear like individual boxes with a gap between them, so they look like the rectangle ad spaces which are both in their own box.

I’ve tried playing around with the CSS but all that does is shift them down slightly instead of making them an individual element in the side bar.

Any help would be great

Thanks

Chris