You don't indicate which field of study the research proposal is intended to cover, and that can make a difference. But in general, you are trying to sell the topic idea itself, which, no matter which field it is, should include presentation of the following points:
1) The research is necessary - That is to say, it hasn't been overdone, or hasn't been debated and presented to death, as it were and thus is worth whatever resources would need to be dedicated to it.
2) Topic is interesting and intriguing - Any good research proposal should intrigue your intended audience. Ask yourself, at the end of this presentation, would they want to research this topic? So try to include a few "hooks" that will get the wheels turning in the heads of your audience.
3) Is it feasible? Your audience should feel very reassured that this is in fact a researchable topic, within a budget if there is one, with known means of research or experimentation.
4) What is the timeline for completion? Open-ended research is often hard to buy in to. Present at least a rough timeline for the research goals you intent to accomplish.
The link included below has a few more suggestions for scientific and literary proposals. Good luck.