Once you have chosen a topic you will need to develop a research question. The five Ws criteria can help you turn your topic into a research question.
Suppose your general topic is global warming. That is a really broad topic! Do some background research to find narrower terms about global warming. Then use the 5 Ws criteria to focus your research.
Who is the population to focus on?
What impacts the who population ?
When is the time frame?
Where is the geographic location?
Why or how is this research meaningful?
Some other subjects related to global warming are: climate change, air pollution, greenhouse gases, weather, pollution control, drought, and flooding. Use a thesaurus to help find narrower and related terms. A narrower term could be the effect of temperature on animals or plants.
Using the 5 Ws criteria, a research question could be:
What is the effect of temperature change on the corn production in Missouri from 2000 to 2015?
What effect did temperature change have on egg production in Des Moines, Iowa from 2010-2015?
What are policies that Mid Missouri could adopt that would reduce flooding on the Missouri River for the next 10 years?
If you can't find information on your topic, you may have narrowed your topic too much. Broaden your topic as needed.