Invite reporters you would like to know better to lunch, breakfast, or some other semi-social activity. This will enable you both to talk informally about yourselves and your work. Ask yourself whether you have a strong contact at each of these. If not, then target them. Make a special effort to introduce yourself to new reporters or those newly assigned to your issues.
Small courtesies can make a big difference, particularly when someone is new on the beat.
Make an offer to help out in any way you can, especially by introducing the new reporter to others in your organization or coalition. Be a continual source of information. You can signal reporters that you have their interest in mind by giving them information you think will be useful to them. Make suggestions on interesting angles to stories and topic areas covered regularly by the selected media. Use your judgment on how often to call or write.