Problem: The methodology chapter follows the literature review. To bring up more clarity and bring back the focus it is always better to recap the main problem that you are dealing with in your research. It is important to succinctly define the problem that you are primarily addressing in the research.
Approach: The approach that you are following for the purpose of primary research needs to be overviewed in the next stage of the structure. The different aspects that need to be catered to here are the rationale, justification, sampling etc. It should not have any kind of ambiguity so that when the reader reads he is ensured that the writer is completely synced with the nuances of the methodology.
Antecedence: it is a good idea to compare the methodology adopted by you with other researches that are similar in your area. Finding similar studies and reviewing them does lend a lot of authority to your research and makes the methodology more concrete.
Validation: It is necessary to give believable reasons for the chosen methodology in your research which is also termed as justification. It is all the more necessary when you have adopted a new or unique type of methodology. A thorough and rigorous justification does add a lot of weight to the research.
Reliability and validity: In all kinds of research, irrespective of the genre, issues that are linked to reliability and validity have to be discussed explicitly. Reliability and validity takes care of accuracy, precision, and error scope in the research.
Sampling: Sampling is important enough to be dealt as a separate sub topic and needs to be given that special attention that it deserves. Sample size has a strong influence on statistical significance and the researcher has to be very cautious and alter when mentioning this in the methodology.
Appendix: There is a lot of material to be added to the methodology chapter that has indirect relevance and has to be added to the end of the dissertation writing in the appendices section. Generally questionnaires and related content can be placed here for reference.
Generalisation of data: each data set has certain scope of generalisation and it should be included in the chapter in terms of the scope of generalisation of data. The more your data has generalised applicability, the wider its use and importance of your research.