A proposal abstract for your research proposal is designed to present an idea of what you will write your research project on. It gives a summary of the project when it has already been complete.
You will need to remember that when you are creating a research proposal abstract, also known as a prospectus, you will have to present your research project to an academic committee or supervisor.
Therefore, it will be vital that you are able to convince them that the project is worth researching. You have to make sure that it rocks, so that you can move on to actually writing the paper instead of spending half of your allotted time for the whole project just trying to get this approval.