From your question ,I believe you want know how to write a quality dissertation .I classify this academic document into 4 : first class, second class, third class and fail.I believe you want to know how to write a first class dissertation,one that will earn you 70% and above. This first step is to communicate thoroughly with your supervisors. Ask them to thoroughly review your work before final submission .Ask for feedback,constructive criticism.. Make them understand you intend writing a first class dissertation. Also,their is a specific dissertation structure you need to follow when writing this type of thesis.It begins with introduction, literature review, methodology,conclusion,recommendation and references. Your introduction must convey your goal and objectives. Background to the study is also important in this section Your literature review must center on current issues that pertain to your particular topic.Also present a statement highlighting the problem that will be researched.In your literature review, choose relevant articles that are current not something that was written in the 80" s,9O"s and early 2000. Your methodology should include the primary/secondary research design,secondary data sources like the textbooks used,specific number of days spent in performing specific tasks like distributing questionnaires, typing ,description of the method of analysis used in your thesis. Your conclusion ,recommendation and references come after this.Your writing style is also important. I will advice you to check online for more tips..how to conclude your work,how to write recommendations and references and what writing style to use. Break a leg!