Designing with the stars....

I dabble in design but am very limited in my knowledge. I would love to hire a professional to give my blog a makeover for the 'new' blog but - alas - I am too cheap for that. Plus, I know that I can do it myself with a little time, research, and effort. It might not be as great but it will be custom and it will be mine.

So here is my question: how do you get the border around your content that separates it from your background?

Some examples (from beautiful blogs):

Heather separates her white content background from her background image with a thick black border








Kimba separates her two solid color backgrounds with a brown border




And Valarie Lea separates her background image from the content with a thick pink border






You can tell I designed my own blog.... no transition....

HELP! THANK YOU!!