Pick a topic that is of interest to you. You might as well enjoy it.
Research is a process and the hardest part is often deciding what to write on, therefore...
committing to a topic, do a preliminary search to make sure there is
material available on the subject and you can complete the assignment
in the time allotted.
Be flexible: during the research
process, you may find it necessary to broaden or narrow the topic. A
well-defined question/issue/problem will need to be identified and
answered for most uppper-division research papers.
topics that may be sensationalist or inappropriate for college level.
You may be fascinated by Vlad the Impaler but it will be difficult to
identify a historical question or issue on the subject which would
satisfy your professor.
Make sure your topic fits the parameters of the assignment