Look back on the sources you've found (citations you've found, etc.) and the notes that you have taken.
Some questions to consider:
- Are you falling victim to confirmation bias?
- Are there any alternate viewpoints or voices?
- Are there any obvious gaps?
- Have the resources you found met your needs, or do you need to ask another question?
Are there any less obvious gaps in your information? Ask a friend, your teacher, a librarian. Seek out an outside perspective to see if there is something you haven't considered!