A dissertation is a long essay (perhaps 15,000 words long) which sets out the results of your own independent and original research. It is based on primary and secondary source material.
Although some of the advice about how to write an essay holds true for writing your dissertation, there are some extra considerations to take into account:-
Do not begin analysing the literature before clarifying in your own mind the research questions that will guide your dissertation. By formulating problems beforehand, you will avoid wasting hours in aimless reading. Know the issues of concern to you and consider the material through this lens alone.
Open your dissertation with a clear statement of your purpose for conducting and writing up new research. These opening remarks need not yet precisely articulate specific research questions, but should indicate the definite direction which the dissertation will follow.
The purpose of an abstract is to summarise in a systematic and formulaic manner the content of your dissertation. The abstract serves as a short-hand for the entire piece, indicating whether or not it would be worthwhile to read. Bear this purpose in mind when drafting your own abstract.
Towards the beginning of your concluding chapter it is useful to restate the findings reached from your recently analysed data. These findings should be stated clearly and with complete precision, forming a proper basis for developing a persuasive conclusion to your dissertation.