The best thing you can do is realize that MCAT o-chem is a freaking joke, and that they try to trick you into making stupid mistakes.
There will be a couple off-the-wall questions about UV spectroscopy, or something else that you might have spent all of two seconds talking about in both semesters of o-chem, and in your MCAT review. You will have a 25% chance of getting this one right.
There might also be some "tough" naming questions. On these, look to see if you can eliminate a couple right away, rather than trying to spend 5 minutes going through all the rules to try and name some horse**** molecule.
I say just practice. Do as many practice problems and practice tests as you can get your hands on.