Hi,
Did you take the EEI practice tests? So your in the ballpark and know what its like? Well the actual test is more challenging than the practice tests. And it is quality over quantity. So you have to have the strategy of doing the easy problems first and coming back to the harder ones later. Dont guess because the wrong answers count against you.
Also the math test given on the POSS varies. Some utilities give the short or long test. The short test has only conversions and a 7 minute time limit. Your lucky if you get that one. I ended up getting the long test. Three sections consisting of conversion, basic algebra, and word problems.
Basically what I recommend is what I'm doing now. Practice. Most people taking the test can probably get a 100% given enough time to take it. But the short time limits is what makes it so challenging. And if your not fresh out of high school or college, your brain can stand to be re-trained to think faster by practicing. The reading comprehension and mechanical aptitude sections were the two sections that had the most time to spare. Also go through the entire forum posts on POSS testing. If you feel your weak on any of the five sections, go through some workbooks recommended on this site and buff up.
Hope this helps.