In order to write an original dissertation the best way is to write your dissertation yourself. Now you have to make sure that you follow some institutional guidelines. Also, develop an original dissertation is by asking you yourself questions at each step of developing an original dissertation.
Why should I write a dissertation? Now if your answer is to get your degree then you will not be able to write a good original dissertation. If your anwer is that you will have an opportunity to explore and find a new school of thought or develop a new ideology then you will succeed in writing an original dissertation.
Where Should I Begin MY Dissertation? If your answer is by choosing a topic then again you will not succeed in writing an original essay. If you say you will start out by conducting a thorough research on the area of study that you are earning your degree in, to find authenticated sources of information which help deduce a hypothesis, then you are on the track to develop a successful original dissertation.
Who Will Help Me? If your answer is that my friends will help me then you will not be able to develop an original dissertation. If your answer is that you will help yourself then you will truly accomplish your goal of writing an original dissertation. You will of course be assigned an advisor who will be an expert in the field you are attempting to write your original dissertation. You can ask your advisor as many questions as you need. Make sure that you attempt to figure out the answer yourself so when you do ask questions from your advisor they will be based on solid ground.