Add seperator between products in product list

Is there a way to include a seperator between products in the product list? Even if it is just a blank line, that would be Ok.

Add some padding around the images on that page using your stylesheet.

Is this the code I need to change?

/Image Display/
#productMainImage, #reviewsInfoDefaultProductImage, #productReviewsDefaultProductImage, #reviewWriteMainImage {
margin:0em 1em 1em 0em ;
}

I tried changing it but it didn't seem to have any affect on the product list page.

You want to pull .productListing-data out of the element the starts with

.centeredContent, .... {
text-align: center;
}

and then

.productListing-data {
text-align: center;
padding-bottom: 1em;
}

or however much space you want.