Learn claims of your School
Today there aren’t existing strict criteria for thesis writing; each institution has its own demands. You need to find out what claims your college has and take them into account; otherwise, if you don't pay attention to this aspect, it can have a negative impact on the evaluation of your work.
Choose theme and discuss it with teacher
You can choose any topic for dissertation, which corresponds to your discipline; every student needs to discuss his chosen topic with his teacher. You can directly ask him "How to start my dissertation". Be confident that you will receive helpful dissertation consulting. You should rely to his experience and take into account his guidance and amendments, no one else can give you such competent answer on how to start your dissertation, how to start dissertation research or plan, etc.
Find similar thesis and study them
After you reached agreement and approval of your paper with teacher, consider making in-depth study of works with analogous to your topics. By making such investigation, you'll learn how to start writing your dissertation, how to structure it and present the material correctly.
Decide what you want to see as end result
Define for yourself, what the purpose of your research and thesis is, what points you want to prove, which ones to refute, etc. You should understand that focus on results will positively affect the outcome of work.
During your research this draft will change numerous times, don't avoid it because it's irreplaceable helper in matter of how to start writing a dissertation and how to do it well. If you can divide your writing process into steps wisely, query how to start writing dissertation won't seem such problematic and stressful.