This worked for me twice, once for the city test, and once for the union test.
I didn't study at all, just went in and took the tests. I knew I needed a 75 to pass, and in reality a 75 is just as good as a 100.
First, I answered all the questions I knew for sure, (minus a few for simply being an idiot), and my score was 55 or 60. Then I did the ones that involved some simple math, but not the complicated ones. That gave me about 10 more points. Next I did the 3 phase diagrams, which I know fairly well, but it's easy to make a mistake. I gave myself half of them, and now had a 70 or 75. The rest I just guessed on, figuring I'd get at least a few right.
I passed both tests on the first try, but they wouldn't tell me what score I got, only that I passed.
Seriously, just go take the thing, if you pass, great, if not you'll know what to study up on. Failing a test is no big deal, though it seems so at the time. Keep at it, eventually you'll get there.