One of the first rules that I learned in my Public Relations classes was to “define your target audience.” With any project or assignment, this is the first step of the process. Once you know who you will be gearing your product or service to, you will be able to figure out the necessary steps you must take to make your product successful. Knowing you want to attract and appeal to will help you formulate your marketing and design technique.
Since you must define your target audience and shape your advertisements so they will appeal to your specific group, you must know what each group is attracted to. Below are examples of socioeconomic groups and the type of publications they prefer. So, let’s get to know our publics:
1. Upper Class- the upper class likes reading information about investments since much of their money comes from investments. They are smart and well educated and spend their money liberally.

2. Middle Class- The Middle Class group like to read information on improving their homes and family lives. They want to know how to live all-around better lives.

3. Working Class- The working class reads self improvement and how-to information. This group prefers lively advertisements and promotions.

Now, these are just the classifications of social class, but you must get to know your public in terms of age and gender too! Knowing the exact characteristics of your public will help you in the PR world!
Here is a helpful article from Public Relations Quarterly, written by Linda P. Morton
http://findarticles.com/p/articles/mi_qa5515/is_199907/ai_n21442800/