I have a guest post idea that I think your readers will love.
It’s called: [title]
Considering that [content type] tends to perform well on [blog name], I think it might be a good fit.
Want me to send you an outline?
I’m [name] and I write at [domain.com]. I’m also a regular contributor at [site].
Anyway, I’m writing to you because I have some really interesting content ideas that I feel would be perfect for [domain.com]’s audience.
I can send you the topics I have in mind if you’re still open to new guest authors.
I appreciate the time, and really looking forward to working together.