The following exercise might help you to understand how to choose an audience based upon your topic.
If you, as a teenager, went to a rowdy party, what would you tell your mother?
Of course, part of your answer rests on what kind of relationship you have with your mom and the fact that, in this scenario, you are a teenager. Discuss what you would tell your mom about the party and if the fact that the audience is your mom would make any difference in your story about the party. Then discuss what you would tell your best friend about the party and then your supervisor. Is it the same version for all three people? If not, why are you telling different stories to the three different people in your life? Do they appreciate different information? In the case of the supervisor, is some explanation needed? In the case of the best friend, is some of the information understood without explanation? Explore how each case is different and why.