To answer your original question, our quant guides are actually numbered, and while you can study them in any order, it may help to go in the same order we use for class: 1) Fractions, Decimals, & Percents, 2) Algebra, 3) Word Problems, 4) Geometry, 5) Number Properties. If geometry is not a big problem area for you, you might actually want to push that last.
To get the most out of each book, you should start by making sure you have the basic idea from each chapter. Do the review problems at the end, and if those aren't going well, go back and review first. If those are fine, hit a few problems from the OG. (We list problems by type in the back of each guide.) Don't do *all* of the problems, though. Do a few and take some time to digest. Move on to other chapters, do some verbal, etc., and then return to the topic later on (days later) to consolidate and extend your learning.
On the verbal side, you definitely don't want to do all of our SC book (or Powerscore's CR book) in one short span of time. Stretch each chapter over a week or more. Read, apply what you've learned to some problems, and flag a few good problems from each set for later review. Then move on to the next chapter, while working in other things (quant, the rest of verbal) throughout the week.
Most importantly, whatever you're studying, take the time to review extensively!