How to produce a good abstract for a thesis or dissertation
The abstract is a summary of the whole thesis or dissertation, and its purpose is to provide a reader with enough information to decide whether to read further. It must therefore be written last, even though it will be placed at the beginning of the thesis or dissertation.
Edit together the main items in the contents list into linked sentences to produce a first shot at an abstract. Although the result will appear somewhat disjointed and messy at this stage, it should show where elaboration, summarising and deletion are required.
Sections from The Research Student's Guide to Success in the chapter on preparing the thesis / dissertation
Finally, edit the result into smoothly flowing text with clear indications in broad terms of the research questions or problems and their answers or solutions.
Use the present tense.