I never did all-ATPs - I worked purely with Gleim's red book. But like many, I just came up with my own memorization scheme. It's been many years, but I know for the long performance problems (the multi-part stuff with fuel burn, time enroute etc), I sat down and laid out the questions and answers and figured out associations- for example (this is just an example, as I can't remember exactly how it went, but it worked): "the longest airplane (747)" just happened to have "the longest time enroute" (of the en route times given). As to weight and balance, I think I made myself some sort of matrix and memorized it, flash card style, so as to be able to write it down. As soon as I got seated and exam time began, I memory-dumped (wrote out) my matrix on the legal scrap-paper allowed in the exam.
One is thus able to dispense with working on questions that might take 20 minutes to calculate, but are worth the same as answers which take 1 second to figure out.
Just in case it ever came up on an oral or in some future interview, I made sure I knew how to do every type of problem- but that is just icing on the cake- memorization will get the written score done.
People doing pilot written exams for European and Canadian certification (JAA), and other exams in the U.S. (for example, Certified Internal Auditor off the bat, I know from a friend) are not so lucky to have this published q&a pool- all the published study materials are merely "samples", and it's therefore a nightmare to prepare for by comparison, so go have fun with some quick memorization- it is not that big a deal, and you dond't have to waste money at all-ATPs (though I hear it is quick and dirty).