Getting started on an undergraduate research proposal
While writing a proposal is not necessarily difficult, doing it right takes careful thought, planning, and dedicated time. If you are concerned that you are not a polished writer, take full advantage of Northwestern's expansive resources, which include your professors, helpful graduate student TAs and tutors, The Writing Place (for peer tutoring), the Writing Program (for courses in writing), the Office of Fellowships, and of course the coordinator of the URGs, Dr. Christopher Hayden, at the Associate Provost's Office.
Dr. Penny Hirsch spoke on proposal writing on January 19: see her slides "So You Have to Write a Proposal" (ppt) or her video on "Turning an Idea into a Proposal."
You can find examples of annotated proposals that have received URG funding in the past, but remember: these proposals went through a number of revisions before they were submitted!
You can also get useful advice from the URG link below and the other related offices.
Useful Links
URG -- NU's Office for Research Grants for Undergraduates
http://undergradresearch.northwestern.edu/ayurg
The Writing Place
http://www.writing.northwestern.edu/
The Writing Program
http://www.writingprogram.northwestern.edu/index.html
The Office of Fellowships
http://www.northwestern.edu/fellowships/