Different blogs have very different approaches to what they write about and where they get their story ideas. For example a blog like Engadget links to other blogs in most posts that it writes - it’s almost like a news aggregator blog and is constantly pointing people to interesting stories on the web. Other blogs rarely link out - not because they’re selfish, but because they are blogs more about original ideas. You are likely to be wasting your time by pitching blogs that never link out.

Also look at HOW the blog links. Do they link to news stories? Do they link to other blogs as ‘examples’ in their posts. Do they link to controversial posts? Do they only link to blogs on certain topics or written in certain styles? The more you learn about HOW another blog links the better position you put yourself in to create your pitch to them.