Ask HN: How do you use Twitter to reach out to press?

I have heard from quite a few people that they use Twitter to reach out to press/writers for their startup. I would be interested to hear specific success stories of how people did this.

A few weeks ago I got into a small conversation with a tech writer from Fortune and an AP writer about a story on the front page of Yahoo. Neither of them follow me and nothing came of it, I am checking to see if I should blatantly ask for a story or try to continue the conversation or...