When considering the research topic, it is good to create a series of questions you would like answered that relate to the topic. This will help you focus your research topic and provide clear indicators for what you hope to achieve through your investigation. Ultimately, this will lead you to one or more research questions, that will form the objective of your research project. Searching the literature will help inform the development of these questions.
The next stage in expanding your research question will depend on what type of research you are conducting.
Quantitative research generally seeks to answer closed-ended questions and will generally include a hypothesis. A hypothesis takes the question and expresses it as a statement, that your research will prove (or disprove).
Qualitative research focuses on open-ended questions. Instead you will seek to explore, describe and explain, and the focus may well evolve and change during the study.
Choosing a topic should also be a joint decision between you and your supervisor and it is important to discuss the research topic as early as possible in your student/supervisor relationship.
Sources: University of Curtin, The University of British Columbia
Knowing clearly what your research question is, will guide your literature search, the selection of a model and/or methodology, your research and data collection and finally, your writing. While you may refine your question over the course of your research, it is impossible to write a good dissertation without a clear and concise research question that seeks to answer your thesis statement.
Before getting too far into things you should:
You will redefine as you discover new resources that better fit your needs, but starting with a specific question or statement is the best way to lay a firm foundation for any research.