There are several different types of media you might want to use.
Newspapers
These can range from local editions with just a few hundred readers to the national dailies that are read by millions. Be very careful about the type of newspaper you approach. Think about who the paper is aimed at and whether they have covered stories like yours before.
Television
News and current affairs programmes on television can attract audiences of millions. Local news programmes also have a lot of viewers. Television news is particularly attracted to visual stories. This sounds obvious, but you are more likely to get coverage if you organise an event or which is interesting to look at.
Radio
There is a huge range of news coverage on local and national radio, and audiences can be as high as for television. You might be able to take part in a radio debate. If you have a good speaker working on your campaign with a knack for catchy phrases, this could be particularly effective.
Magazines
Some specialist and trade magazines have small circulations. But the readership will be more passionate about specific issues. Also, longer deadlines mean that they are often able to print more involved features.
Online and new media
Many news organisations have their own websites. Sometimes they re-use stories from elsewhere but there is often a dedicated team of journalists producing their own stories. The bigger sites can register millions of readers every day, including a large international audience. But beyond this, you can now simply put out your own message quite easily on sites such as youtube, or create podcasts and articles on your own website.