Can u specify what kind of suggestions do you need? I mean most of the part is similar to writing M.Sc. thesis. The only difference is that, you need to elaborate the steps and procedures.
Most institutions have their specification so it can't be generalize. So the first thing is to know the institution you want to send your proposal then get their specification.
Determine your area of interest and choose an appropriate supervisor(s) from some institute working on your area of interest. Go through their recent publications and research profile. Read the publications, especially the discussion, introduction and further suggestions part . Think and design the project.