Now that you have background knowledge about your topic, think of keywords you could use to search for sources. Use this interactive tool to help you organize your keywords, or try creating a concept map. You can use the questions below to help you.
Example topic - mass incarceration
Then combine your keywords from each answer using AND and OR.
Example Search in Academic Search Complete:
This work is licensed under a Creative Commons Attribution-NonCommercial 2.0 Generic License.