If your professor has not assigned you a topic, choose an area of interest.
Do some background research using a specialized subject encyclopedia, reference book, handbook, etc. In this step you can
Narrow to research question
Narrow the subject into a research question and start an outline. The VU Writing Studio has a great handout on this topic.
Type and amount of info
How long is your paper? A five page paper may require fewer sources than does a ten page paper. Has your professor asked you to use specific types of sources (e.g. scholarly, peer reviewed articles, books, newspaper articles, statistics)?
Choose tools to search
Select a subject specific database or Library Catalog. Search for information you think can help you with your paper topic. This is also a good time to select your search terms based on your topic.
Evaluate search results/sources
Look at your results, author credentials, read abstracts, skim the articles. Do the articles help you accomplish your purpose? Don't rely on database ranking to do this for you.
Apply sources to your paper
This is the stage where you connect your research to your writing. For articles you find helpful, you may want to take notes or summarize. This handout from the VU Writing Studio provides more detail.
Repeat as necessary
Once you've started writing, you may find that you need additional sources for your paper. You may want to change your search terms when searching a database or select another database. Add additional sources to your paper.