Whenever possible, choose a topic that you feel passionate about. Writing about something you enjoy certainly shows in the final product, making it more likely that you will be successful writing a paper about something you enjoy.
Whenever possible, look for peer-reviewed empirical research. These are articles or books written by experts in your field of interest, whose work has been read and vouched for by other experts in the same field. These can be found in scientific journals or via an online search.
To draw a parallel, a lawyer researches and reads about many cases and uses them to support their own case. A scientist reads many case studies to support an idea about a scientific principle. In the same way, a history student writing about the Vietnam War might read newspaper articles and books and interview veterans to develop and/or confirm a viewpoint and support it with evidence.
You need to understand completely that you are not writing a descriptive essay. A research paper is an accurate and thorough work, which is based on facts details. You cannot add watery text about anything into the paper. Your statement should be supported with examples or reference other profound research and academical works.