Hey there. I'm a professional GRE tutor as well as editor. Like the original poster, I too graduated from a top law program, so I understand the difference between legal writing and the writing that is required on the GRE.
The essays are graded by computer (so don't deconstruct the essay format, please) and test your ability to do several things:
CONTENT
ORGANIZATION
DEVELOPMENT
WRITING STYLE/CLARITY
The most important thing is the content (do you have good points to talk about?), development (do you back up your ideas with reasons, evidence?) and clarity (can you communicate your points?).
I'm actually an excellent scorer and reviewer of essays. My predictions are pretty accurate. If you want me to do a quick review, I am happy to do it for free. Just contact me first and I'll give you may email address, or to to www.testheads.vpweb.com and you can contact me that way.
Theresa Gheen
Managing Member
Test Heads Educational Coaching, LLC
www.testheads.vpweb.com