That is a very general question. What exactly do you need help with? Not to mention the fact that each school expect different types of content.
In general however, your proposal should include the potential questions for your essay (look at the syllabus for more this), some background details on your topic as well as the areas you will concentrate more (so basically narrowing it down, start describing it on a broad sense and then slowly give the potential directions that your project will focus on) and the potential sources that you can use.
This is a very broad explanation however.
Reply if you need anymore help.