Once you've read a little bit about the topic, you'll want to take a stand.
What is THE POINT you want to make when writing your paper or doing your presentation?
It may seem to you that taking on a subject broadly, such as "bullying," would be easier than focusing on one aspect of the issue. You'd have a lot to write about. Right? In fact the opposite is true. You'll find it easier to research and write about a topic if you focus. A broad topic is overwhelming, and you'll quickly become frustrated and confused by what you should or should not include. The background sources will help you focus.
Here are just a few more specific topics related to bullying, for example, that will result in better papers and more coherent arguments: