Moreover, for best dissertation grades, you need to be well-versed of a correct dissertation structure. A common dissertation structured preferred by most of the universities are as follows:

Dissertation Title Page
Dissertation Acknowledgement
Dissertation Abstract Page
Dissertation Introduction
Dissertation Literature Review
Dissertation Methodology
Dissertation Data Analysis & Results
Dissertation Conclusion/Future Outlook
References & Appendixes

For each of the above dissertation chapter we need to follow the correct structure and organization. And more important thing to consider is a citation style as per the guidelines of your supervisor. The most common citation styles are:

MLA
APA
AMA
Chicago
Harvard
Turbian

Make sure that you follow the guidelines provided by your University & your supervisor with respect to your dissertation assignment.