I recommend College Essay Guy's guided exercises to help students brainstorm their essays. He has a ton of FREE exercises on his site such as "Feelings and Needs," "Values Exercise," "Essence Objects" that are all worthy of a try. And he offers tons of free resources and sample essays.
I use his exercises in my own practice, in addition to my Personal Imagery Method and Brushstrokes.
College Essay Guy also offers an option to pay-what-you-can for his online courses, and he offers scholarships for one-on-one college guidance. Explore his site to find these resources.
Another interesting site is AdmitSee.com which has actual college students on it sharing their actual applications for a fee. If you're from a low-income background, AdmitSee will provide free access to five students' profiles and their essays for various colleges.
Don't forget YouTube! There are plenty of college students reading their own essays aloud and offering free guidance. I found this Harvard student particularly wholesome.
Finally, I have a nice collection of essays from former students and clients who were admitted to top colleges. Contact me for free access!
BEST WISHES ON YOUR ESSAYS! Most students regret that they didn't start earlier, so hop to it!