Determine whether a hypothesis is necessary before you decide when to form one. Not all research proposals contain hypotheses and it may not be required by your professor. Talk to your professor about your research project to decide whether it will be beneficial to include a hypothesis.
Distinguish between a hypothesis and your research question. Some academic departments will use the term hypothesis to approximate what is also called the research question. A research question is a necessary element for a research proposal and will help guide the literature review process. If you formulate a research question before you conduct a literature review, you will be able to search for publications that address the research question. If your hypothesis is essentially a research question, it is best to determine your hypothesis before you began your literature review.
Be flexible when conducting your literature review. As you read the publications related to your area of research, you may encounter new information that will influence how you approach your research proposal. Even if you have already formulated a hypothesis or research question before conducting your literature review, you can change it at any time prior to submitting your finished research proposal. It is important to communicate regularly about your research with your professor who will be able to provide valuable feedback about changing your hypothesis while you conduct the literature review.
Evaluate your hypothesis when you have finished your literature review. Whether you conduct a literature review without a clearly established hypothesis, change your hypothesis or maintain your original hypothesis, consider whether your literature review shows that the research is warranted. Depending on your academic department, you may be discouraged from proposing research which has already been done. Often the literature review is used to prove that there is a gap in the literature that your proposed research will fill. However, only your professor knows what hypothesis your academic department will be inclined to support.