Yes, that's right. I know it's not easy to call people you don't know. Don't wait for an organization to announce a vacancy before expressing an interest in working there. If you wait, you will compete with all the other applicants who have responded to the announcement. Beat the crowd by getting your materials in ahead of time.
Persistence wins job offers.
Establish a schedule for follow-up phone calls and correspondence. Take your cues from your correspondents regarding the frequency and methods of your follow-up contact. Suggest a time when you will call again. See how your correspondent responds. Hiring often doesn't happen overnight.