What is a thesis?
Your thesis should be your main point. Your paper should support and analyze that point.
What do you want your audience to learn from your paper?
Think of your thesis as an umbrella. Everything in the body of the paper needs to fit under that umbrella. If your thesis discusses the economic dangers of downloading and stealing music, then you shouldn’t discuss different artists and their effect on society in the body of your paper. Both topics have to do with music, but your original point shifts from the economic state of the music industry to societal changes made by an artist.
Here are some suggestions as you work on your thesis: