Though my hub does not talk about how to write a research proposal (and a good one at that), I suggest that you ask yourself what topics would you like to examine further. For instance, if the field is broad like health, then list down health-related topics that you find interesting. Choose 1-3 issues that you would like to explore. Why more than one? Just for contingency in case, the others seem harder to do, if not impossible. The format, criteria, and requirements will depend on your teacher, the funding agency, and your preferred academic program/department at your chosen college or university.
Based on experience, a research proposal is considered "good" if it offers clear purpose/objectives, methods, potential benefits to stakeholders, and budget (if applicable). Some organizations ask for monitoring, evaluation, and sustainability plans. There are also agencies and assessors who are meticulous when it comes to the use of the English language, particularly grammar and spelling. Thus, you might want to hire a professional editor and a proofreader to help you polish your research proposal. Otherwise, there are online materials that you can use to help you improve your English writing skills.
I hope you will find this response somehow useful. Otherwise, please conduct further research on what makes "a good research proposal."