Supplying good stories takes nurturing. You just can't produce a good story for the press by listening to your client every once in a while. You literally have to work with them, go on sales calls, learn their challenges and solutions. After that you have to develop trends and fresh new angles that fit the needs of the press. Treat the press with the utmost of respect.
Clients come and go, but members of the press usually cover their beat for a long, long time.
You can't abuse their service. Even if you pitch them the best story in the world, they are still doing you a favor by writing or producing it. They owe you nothing. Don't just call the press when you need them. You need to develop a relationship with them even if it is just over the telephone.