If you find far too much background information on your topic, consider picking a sub-topic that interests you. Use search vocabulary you labeled "narrower topic" in Step 2.
If you find far too little background information on your topic, consider choosing a broader topic. Use search vocabulary you labeled "broader topic."
You can often find narrower and broader topics by revisiting the background information you found about your topic in Step 3.
Personality is a broad topic in the field of psychology. You could narrow down in a number of ways, such as by focusing on one or more:
These examples could be further narrowed, or you combine different subtopics (e.g., personality testing in the workplace).
If, on the other hand, you started with a very narrow topic like using personality theories to predict children's aggressive behaviors during playground games, you may simply find there isn't much (if any) research that's been done on this topic. This doesn't mean you need to throw out your topic entirely! Instead, consider other types of information that would be helpful to you, such as children and personality theories and behavior in playground games.