Three vitally important things that a thesis should have:

(1) Have a `thesis' of the thesis
A review of 139 examiners' reports ... revealed that rarely were theses criticised for `bad writing' in the sense that most people understand that phrase. That is, theses were acceptable in terms of the mechanics of presentation: sentence structure, paragraphing, spelling, grammar, etc. They also were not criticised for failing to conform to conventions of the discipline about referencing or presentation of data. What frequently was criticised was the students' failure to take a clear philosophic stance or to reach a conclusion. Examiners called upon students to state clearly their hypothesis and their conclusions. If students adequately communicate the `thesis' of their dissertations, they usually avoid unnecessary length, lack of coherence, repetitiousness and confusion in their writing.

Supervisors need to emphasise throughout students' candidacies that they are striving in the thesis to communicate one big idea; that there should be a `thesis' or centre to which everything in the document contributes. (Nightingale 1992, p. 174)

... so, what is my thesis?

(Source: http://www.ee.nus.edu.sg/stfpage/eleamk/phd/phdth3.html)