How do you find a blog ? The answer depends on what you really need to know.
If you want to search a definite Blog then here are the ways.
Go to Google.com search Engine
Then in the Left hand side click more then click Blogs Then you will be able to find any blogs under your search command.
If you want to search Blogs by categories then go to blogsearchengine.com You can use this to get relevant backlinks for your keyword.
If you need to know "how to blog" or "how to blog free" then see my Blogging guide in the Categories list in right hand side