Content marketer Sujan Patel shares eight tips for successful PR pitches. As a writer for Forbes, Inc and other places, he receives over 100 pitches a day. He's also sent quite a few pitches himself, which is how Sujan got to write for those popular publications in the first place. So it's safe to say he knows a thing or two about pitching.
If you're a startup without a brand, credibility or budget, then DIY PR may be your best choice for getting traction. Here's a good introduction of what you'll need to get started, including some tools you man find helpful.