What are your research questions? To what extent can you test them? How would you justify the viability of your questions?
Why would this design be the most appropriate for answering the research questions? Conversely, why would quantitative and mixed methods not be appropriate?
What approach would you select for this study (ethnography, grounded theory, case study, phenomenology, narrative)?
Why is that approach the most appropriate one for answering the research questions?
What theoretical framework or perspective would you use?
What would be your role as the researcher?
What is your target population? How would you identify and recruit participants?
What factors would contribute to determining appropriate sample size? You will not need to calculate sample size for this assignment.
If appropriate for your plan, what instruments might you need?
What data collection procedures might you use?
Why would those be the most appropriate methods to use? How would that data help to answer your research question(s)?
How would you ensure quality and reliability of data?
What are threats to validity? How might you mitigate them?
How might you analyze the data?
What are the ethical considerations related to the plan?