Others can speak to this more directly, but like all tests, dont get stuck on one question. Answer best choice then answer the easier ones, then go back and correct and double check. Unanswered questions don't get any score at all. This doesn't mean you should not bone up on the math/geometry/mechanical basics as well as some of the higher level stuff.
You pretty much need to ace this thing, Local 6 takes about 100 or so now out of many thousands. (Due to the high pay when or if you get hired down the line. One of the highest in the country, if not the whole state. People come out of the wood work to take it.)
FYI there is a very nice family owned burger joint further south on Mission if you do get in. And a very good steak and cheese sub up the street from the hall on Fillmore.