Hi Sierra,
I’m doing a similar process myself. I started by visiting blog similar to mine who accept advertising. I created a simple chart that included their rates (often listed on a blog page), number of subscribers, FB fans, or any other info I could find. Now I just have to compose my rate sheet.
The other thing I did was create a statement on my blog about the types of ads I’d accept. It’s nice to have something to point to when businesses approach you. Here’s mine: http://www.somethingwagging.com/pr-friendly-advertising-and-disclaimers/
Hope this helps and that others share their advice. But given how busy people are around the holidays you might want to try again after the new year. 🙂
Good luck
Pamela
Pamela Douglas Webster
An Amateur’s Musings on Dogs and Their People
“Outside of a dog, a book is a man’s best friend. Inside of a dog, it’s too dark to read.” – Groucho Marx