Think about whether you have framed your topic so that it can be debated.
For instance, illegal immigration. This is a general topic that might be a starting point, but in and of itself it is not very controversial. On the whole most people do not think that having immigrants come to the United States illegally is a great situation. Where people disagree is what we should do about it.
grant birthright citizenship or not?
build more fences/hire more border guards?
deport illegal immigrants, especially children?
grant in-state college tuition to illegal immigrants?
Think about the scope and main points of your topic BEFORE you begin searching for sources.
What is the issue? Can you articulate it?
Is there a particular group of people that is impacted by this issue? Drivers? College students? People who like to shop online?
Is there a particular geographic location that is the focus of your research? Orlando? Florida in general? The United States as a whole? Some other country or community?
Controversial topics come and go, and even the ones that remain popular for a long time can see a shift in opinion. Think carefully about how recent the information needs to be and check the dates of your articles as you go along. Many databases allow you to limit by date, so consider that aspect as well. Do you want only the last few months? a year? a few years?
Why is this issue important?
What solutions to this problem do you see?
What objections might someone have to your argument?
Continue to revisit these as you find and read sources, refine your topic, and develop your thesis statement.