It might feel like a weird use of tutoring time, but having your GRE tutor watch you take a practice section is highly recommended. You'll get feedback on your test-taking and timing that you won't be able to get any other way.

Here's how it might work:

1. The session(s) where the tutor observes should be toward the end of your prep, when you've ostensibly mastered foundation and strategy and developed a deep database of experience through doing and analyzing lots of questions. You should have done at least some timed work and practiced your timing strategies before the session.
2. Ideally, the tutor can see what you're writing, so use a tablet or similar device.
3. It should be a new section you haven't seen before, like one of the practice sets in the new ETS Official Guide.
4. The tutor shouldn't talk - they are there to observe, and to record how long you spend on a question, and how long it takes you to skip a question when you skip.
5. Don't worry about impressing your tutor. Just pretend they're not there and take the section as you normally would. Due to logistics, you may have to tell them what question you're on, but that's it.

In my experience doing this for the first time with someone, I am usually surprised that they are usually quite a bit worse than I thought at things like using timing strategies and quant strategies. By watching them take a section, I can get insight beyond what I would get from merely quizzing them on their strategies, which allows me to give them tailored feedback.

But Vince, aren't GRE tutors really expensive? Check out the Gregmat tutors - any one of them can help, and they're much more affordable than the industry average. This is a highly recommended investment, and you'll get a lot of useful feedback even if you only do it once.