As you get more into your research, you start to understand that research is a conversation. People are having conversations about your topic. These conversations can be found in the scholarly literature, as well as other formats. As a researcher, your job is to access, explore and evaluate the conversation as it occurs in these sources. Once you understand the shape of the conversation, you can contribute your own ideas.
As you turn your topic into a research question or hypothesis, you'll have a clearer sense of the conversation. You'll have an idea of what you want to explore further & what questions you want to ask related to the topic. Don't worry about having the question set in stone before you start doing research. Research is also a conversation between you and your sources & your topic/question.
CHECK IN: Can you answer these questions: How are experts discussing your topic? What themes do they consider? What common questions do people debate? What is the scope of the topic? (Are scholars discussing your entire topic or pieces of it?) Who is having the conversation – are you seeing the same names mentioned in the citations again and again?
As you find books and articles, pay attention to what the author of a useful source says about other scholars in the field. Most scholarly articles and books have a section where they discuss the scholars that impacted their own present work. Look for phrases like "So and so is a key leader in the field" or "So and so's methodology impact our work in significant ways" or "We disagree with so and so in these ways."
Note the scholars that your original source describes as significant. Then go find the books and articles those scholars wrote. This is how you trace the conversation happening around your topic. By tracing cited works, you will find connections that you would otherwise miss. You will discover the patterns of the conversation around your topic. This is the way most scholars search for sources, so if you also search this way, you'll be searching in a very sophisticated and informed manner.
How to do a bibliographic trace: Search for cited books by title or author in library catalogs; for journal articles, check the Do We Have This Journal by journal name to see if we have the full text of an article. Several databases also include features telling you how often a work has been cited (like the ones below). Use Tracking Down Materials for more pointers on how to find hard copies. Please also contact any librarian if you need help at any point of this process.
You can (and should) also go forward in time to see who has cited your original source.