Communicate in a few sentences what’s new and interesting about your story, how timely it is, why you think they’d be interested, and how you can connect them to relevant people or information. Reference past articles or their interests, compliment them on the way they approached an issue. For example, you can tell them past coverage was fair, balanced, or insightful. Address them by first name with a friendly hello. Follow up after you've given them a little time to get back. Here is template you can reference:
Hi [Name of Journalist],
I deeply appreciated your article on [_____] and the coverage you’ve provided, and thought that you might be interested in hearing about this [upcoming event]. You can find more information about it here [LINK].
I’d be happy to answer any questions, or put you in touch with someone for interviews or further comment.
Best Regards,
[Your Name]