Write about breaking news. Piggyback on headlines. What's compelling to you isn't always news, but what's news is always compelling. Don't call journalists late in the afternoon. If there is no consistent contact, they're going to forget about you.
Regular contact is important.
Put a human face on your story. Nothing sells like a human face. You need to have your facts and figures, your statistics, but a human face will trump your facts. You want to give an example of how your issue will impact your neighbor, your community. Many smaller newspapers will only take stories with a local angle.