If you want to write a good dissertation then you need to create good research questions. Your research questions must be focused on few things:
Students should focus on a single issue so that they can have deep understanding about the topics.
Questions of your dissertation should be based on research.
It should be possible to answer all the questions within the timeline.
Your answer should be thorough enough.
Your question should be relevant which can relate to the topic.
Your research question should be suitable for your research and it should be more useful for society.
Your research topic should cover a broad area of society.
You should have a reading of the dissertation so that you can understand the issues discussed in the dissertation.