There is no such thing as the "general public" in nonprofit marketing!
The "general public" includes everyone from your three-year-old neighbor to your eighty-year-old grandma. It includes Wall Street brokers, single moms, cowboys, transvestites, and everyone up and down your street and in your office building. Do you care what every single one of these people think about your issues and organization? If you are smart, the answer is NO!
To be successful, your nonprofit needs to reach out to a specific subset of the general public, not to everyone. Only a small percentage of the general public is interested in what you are doing and can be motivated by you to help you achieve your mission.
So if you aren't communicating with the general public, who are you reaching out to?
Start with three imaginary friends of your organization or people you are trying to influence. Describe these people in vivid detail. How old are they? Pick a specific number, not a range. Male or female? Age? Ethnicity? Education? Jobs? Hobbies? What clothes do they wear? What cars do they drive? What do they do on weekends? What TV programs do they watch? Think of as many details as you can to bring these three people to life and then give them names. Scan the stock photography sites and find photos that resemble these people you've created.
Now, develop your communications strategy for these three people. The 80-20 rule applies here. If you talk to these three people, you will do a good job at reaching 80% of the people who really matter to you. Don't worry about the other 20%. After all, if you've been writing for the general public, you've been reaching 0%.