This guide includes an outline that looks like a "fill-in the blanks model" and, while in the abstract all proposals are similar, each proposal will have its own particular variation on the basic theme.
Each research project is different and each needs a specifically tailored proposal to bring it into focus. In the end, they may well all be interpretations of observations, and differentiated by the rules that constrain the interpretation.
It includes a model outline, but advisor, committee and funding agency expectations vary and your proposal will be a variation on this basic theme.
The same principles apply to dissertation proposals and to proposals to most funding agencies.
Different advisors, committees and agencies have different expectations and you should find out what these are as early as possible; ask your advisor for advice on this. (Different advisors will have different preferences about the rules, the meta-discourse, in which we all work.) In the abstract all proposals are very similar.
Further, different types of thesis require slightly different proposals. They need to show a reasonably informed reader why a particular topic is important to address and how you will do it.(One 'old saw' about research in the social sciences is that the finding is always: "some do and some don't".Try to avoid such insight-less findings; finding "who do and who don't" is better.) One problem with this type of project is that it is often impossible to tell when you are "done".(Of course you will have to write the thesis in acceptable form, and you probably will discover things in the course of your research that were not anticipated but which should be addressed in your thesis, but the minimum core intellectual contribution of your thesis will be set by the proposal.) Both parties benefit from an agreed upon plan.The objective in writing a proposal is to describe what you will do, why it should be done, how you will do it and what you expect will result.Proposal writing is important to your pursuit of a graduate degree.The proposal is, in effect, an intellectual scholastic (not legal) contract between you and your committee.The proposal should situate the work in the literature, it should show why this is an (if not the most) important question to answer in the field, and convince your committee (the skeptical readers that they are) that your approach will in fact result in an answer to the question.Theses which address research questions that can be answered by making plan-able observations (and applying hypothesis testing or model selection techniques) are preferred and perhaps the easiest to write.A clean, well thought-out, proposal forms the backbone for the thesis itself.The structures are identical and through the miracle of word-processing, your proposal will probably become your thesis. Once you have a good idea, you can draft the proposal in an evening.