The best publicity (from your point of view) comes with a story that keeps going, hour after hour, day after day. Once a story reaches the point where there is nothing new to be said, it dies. The news media talk about stories that still have "mileage" in them, and will keep using them if they still appeal.
So when you put out a statement about an issue, always think several moves ahead, as you would in a game of chess. You will probably be able to predict the response from your competitors. Have a response to that already prepared, so that you can keep the story alive. Better still, challenge someone by name (or by company) to respond in your original statement. That will virtually guarantee extra coverage. For example, a pressure group might accuse a corporation of some serious misbehaviour. There will inevitably be a reply, although "no comment" is also useful to the cause.
In order to give your story as much mileage as you can, make sure that you are always available for a comment. If the story breaks at 10am, give the reporter your phone number and make sure your phone is by your side (yes, even on the bedside table) for at least the next 48 hours. Many stories die because the main players can't, or won't make further comment.
A really big story can be revisited on its anniversary, or when something happens to a company mentioned in the story. Keep an eye out for opportunities and give your story as much mileage as possible.