In a word… very. That's not meant to oversimplify. No doubt you've heard that the essay is the best way for an admissions officer to learn about who you really are. Your grades and test scores aren't the things that define an applicant. If they were, why would colleges ask for more?
Joyce Carol Oats said "…as soon as you connect with your true subject you will write". No matter what question the essay actually poses, underneath it all the real question these schools want to know is "who are you?"
It's a hard question to answer. Don't know where to start? Still struggling? No matter where you are in this process, these three starting points can help you find your topic.
1. Free write
Forget about the essay topic at hand. Set a timer for 5 minutes and don't pick your pen up from the paper. Don't worry about grammar or whether or not it makes sense. Is there still time left on the clock? Keep writing. When you're done, underline any ideas you think might be worth expanding.
2. Idea clusters
Maybe you already know your writing topic. Write it down in the middle of a blank piece of paper and circle it. Any ideas related to your main idea will be connected to this with line and another circle. Any ideas worth exploring? Try free writing (see above).
3. Say it out loud
This is how I would start a session with a client. If you're having trouble getting the ideas from your head to the page, talk it out. Tell a story. Keep a notebook next to you when you have a brainwave, but keep going. If you're feeling inspired at the end of the conversation, dive right in and write!
You'll do several revisions of the essay, so don't worry about it being perfect from the get-go. Hopefully you'll find that the more you get into it, the more you'll find to write about.
One note to parents--try to be as hands-off as you can be during this process. Not only is this a critical part of the application, but it's also a very draining. Proofread it, don't edit. There's an important distinction there.
There are no bad topics, just bad writing. (It's an essay about YOU, how can that be a bad topic?) Just be thoughtful.