This might be overkill, but a company called EnglishClub.com posted an entire, online crash-course in writing college admissions essays on their site. It claims to be from a professional essay-writing service (EssaysEdge) that you would pay big bucks to use. Click on the car crash for the course:
You don’t necessarily need to read or work the entire course, but click on topics that might help you. I thought their advice on writing conclusions, “Conclusions: Do’s and Don’ts” was pretty solid.