Good question! I'm writing mine at the moment and wondering the same thing. I'm in humanities so I might not be able to help, but I can tell you what I've been told so for. Basically I keep being told to make some bold conclusions. They will change once you're on the course, but I think they want to know what you think you might find. The general structure, flow and readability of the propsal seems to be paramount, as does the reasons why you think the research should be undertaken, and why you think you're the best person for the job. Vague, nut hope it helps... Good Luck!