Write down five or more angles you can use to approach the topic. For example, if your broader topic is consumerism, you might list specific aspects of consumerism you want to explore more in-depth. In this case, potential angles could be advertising, brand name versus discount clothing or debt. At this point, your topic still needs work, but you're closer to honing in on a topic.
Look for nuances in your angles that might lead to a more specific study. Using the advertising angle under the consumerism umbrella, for instance, you might focus your research on the impact of advertising on the teenage population.
Settle on one particular thread of interest and make it as specific as possible. Although "the impact of advertising on the teenage population" is much narrower than consumerism, the topic is still far too broad to cover effectively in a high school or undergraduate essay. To further focus your topic, add even more specificity to your angle. For example, you might address the role clothing ads play in self-esteem issues of teenage girls. In this scenario, you might focus on how ads targeting teenage girls sell a certain image, or impact social acceptance.You could get even more specific by focusing on a certain clothing line or a particular demographic.
Run your ideas by your professor. Whether you're analyzing a piece of literature, or a cultural phenomenon, settling on a specific target can be the most challenging step in writing your best essay. Your teacher may be able to help you tweak your topic after you've done the initial work, or confirm that your topic is ready to go.