Decide on a specific topic within psychology on which you want to conduct research. This is the topic on which you will chat with your research team about on discussion board assignments and ultimately write your research proposal.
Conduct a literature search on the topic using PsycINFO. As you go, you might find that you need to narrow down your topic. Feel free to do so. (For example, if your topic is simply goal setting, you will probably find hundreds or thousands of papers on goal setting. You need to narrow that down to something like goal revision or goal conflict to get a manageable list.)