Relationship blogging is not all about the pitch, though. You can't just go barging in on someone else's blog and start pitching your wares. You will not be welcome even if your wares are related to the blog. At first, that is.
What you need to do is read, read, and read some more to get the feeling of the blog and those who are posting on that blog. Then you need to start participating and posting yourself. You need to become a part of the "community" you want to pitch well before any pitching goes on.
One word of caution, though, make sure you are relevant to the blog you are pitching, or want to pitch. Too many times blogs get pitched and have nothing to do with the pitch whatsoever.
To get a good idea of the topic of the blog, look back at the previous posts and the categories of topics discussed. If your pitch differs from any of these then do not embarrass yourself by trying to pitch that particular blog. Move on and find one that your pitch will be compatible with. Continue here...