first of all,..your proposal topic must be related to your academic background/experience ( if not still ok, but you need to do extra work to fully master your proposal topic.
ii) the proposal topic is novel (something new and potentially to be developed)
iii) topic is relevant and associable with your supervisor expertise/field and potentially to be commercialize (this will help to get scholarship)

blueprint of proposal including:-
i) topic
ii) problematic
iii) methodology
iv) hypothesis

topic:-
your proposal topic

problematic:-
the current problem (what has been done, what do you look for, how was it done) and how your proposal topic (theoretically) work to solve the problem

methodology:-
experimental section : refer journals and come up with your own methodology which is superior or on par(at least) with current methodology/process/solution.

hypothesis :-
conclusion/summary from your experiment/analysis/observation this including every field (science/engineering/it/business/politic science n etc