Structure
A dissertation is truly a scholarly document, and should contain extensive references to the works of experts in the related field, which has to be done in the form of citations to journal articles, books and monographs. Dissertations often contain an empirical component that reflects some independent study or data gathering (incorporating questionnaires, interviews, standardized instrument) An empirical study can be quantitative, qualitative, or descriptive. A dissertation can be strictly historical and can be based primarily on an extensive literature review. There can be a number of variations on how dissertations should be structured. Dissertation writers can possibly invent their own ways and deviate from the standard dissertation process.

A dissertation is not a typical paper it's a different kind of academic project though it may share some characteristics with journal articles and research writings. In addition it's neither a collection of abstracts; and or annotated bibliography; it's also not a descriptive overview about a topic; neither a discussion of a writer's personal viewpoint.
Dissertations: How it should be organized
Under normal circumstances dissertations have to follow a five chapter format: first being the Introduction (complete with traditional subheadings); The Literature Review; Methodology of the research, then comes a chapter on the findings; Lastly it has to be a Conclusion, summery or Implications. A dissertation also has Appendices (sources of instruments and permission letters, for example). And then there is a References list.
Dissertations can be written in a number of formats, the APA format is very popular. There are some universities that provide style-sheets which help augmenting the APA format which specifically conform to APA standards. MLA is also a popular format and is used quite often for subjects like literature. In addition to these other popular dissertation writing and referencing formats include Harvard and Chicago.

Dissertations should always be presentable and should be written in a systematic manner. Chapters should be clearly indicated footnotes and endnotes (if required) should be complete accordingly. Unlike essays and journal articles, dissertations should use a higher level of language as these documents are seriously scholarly documents and the dissertation writer has painstakingly researched a subject with a good deal of time and knowledge. A dissertation should also have a page dedicated specially to all those who have helped in making the dissertation. At times it can be a big list of teachers from the university or college, colleagues, friends and the likes. All should be thanked for their work and efforts!