What is the best study guide to use for the PSAT/NMSQT in your opinion and why?

Alright. The best guide by far to use was the official student guide, as the questions on there were geared as close as possible as the ones on the real test. In terms of general study material, use Kaplan or the Princeton Review (I personally used Kaplan), but beware of Kaplan's practice tests - they are by far more difficult and asinine than the actual PSAT tests, and they literally left one question unfinished midsentence, forcing me to figure out the answer from the five solutions given. Don't worry if the math section seems harder - you'll learn much of the stuff on the test this year, given you're in honors cles. Aside from that, focus a fair section on grammar (that will boost your score up the most if you have trouble there - it's by far the easiest and quickest section to learn), and then just work on your reading comprehension and vocabulary. Most guides are the same, but stick to something reputable - feel free to use SAT study guides as well, such as the Official SAT Online Course offered by the CollegeBoard itself, as the similarities between the PSAT and SAT are almost entire. Good luck. Again, save the Official PSAT Student Guide Practice Test for last, after all your studying and practicing, so you can get a feel for what your score will really be on the test, as the other practice guides do a terrible job (I got a 134 on the Official Practice, 12x on the Kaplan Practice taken afterwards). Enjoy your testing.