Part of being a researcher is identifying a research question. One of your goals will be to articulate a research question that is an appropriate scope (not too broad or narrow), is arguable (not a yes / no question), and that has social significance (stands up under the who cares question).
The following handout includes research questions for discussion.
Keys for Writers (Raimes and Miller-Cochran) include useful information to consider as you form an arguable claim (thesis). Avoid the following since they are not debatable.
The book also provides examples and key points (pg. 53) for a good working thesis.