What are the basic guidelines to write a project proposal?

The proposal is, in effect, an intellectual work that will create contract between you and donor. It specifies what you will do, how you will do it, and how you will interpret the results. In specifying what will be done it also gives criteria for determining whether it is done. In approving the proposal, your donor gives their best judgment that the approach to the research is reasonable and likely to yield the anticipated results. They are implicitly agreeing that they will accept the result as adequate for the purpose of granting a donations / grant. (Of course you will have to write the proposal 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 proposal , but the minimum core intellectual contribution of your thesis will be set by the proposal.) Both parties benefit from an agreed upon plan.