mayqlaf on "Too much space between paragraphs"

I'd like to know how to decrease the space between paragraphs.

I'm using the code: <b>

It does insert a blank line, but it is much too big of a space. I would like it be about half of what it is. Here's the link if you want to see what I'm talking about: http://nickarnette.com/blog/

Also, I'd like to have some blank space at the bottom of each post. The <b> isn't adding a space at all.

Thanks for your help!