How to NOT run out of College Board material

So after talking about various strategies for coping with a dearth (or a paucity) of College Board materials, I'm going to make some suggestions for how you can avoid running out in the first place. 

First, take a good, hard look at your scores on the tests you've taken so far. 

If your score is consistently increasing on each test you take (not just 30 points up, then 20 points down), you don't need to worry so much. By the time you get through all ten tests in the College Board book, you'll probably be more or less where you want to be (and if you're not, see here and here for some ideas on how to proceed). 

If, on the other hand, you've taken a bunch of tests and your scores have been in the same general range on all of them, that's a sign that you're not spending enough time on the areas you really need to work on. You don't need to repeatedly take full practice tests "just to get comfortable;" familiarity does not equal mastery.

Forget about the test for a few day or a week (or two or three), and just focus on building the underlying skills. It might be painful -- and it certainly feels less gratifying than going through lots of practice material -- but  need to go and get solid on the fundamentals before you go back to the test. You can't apply knowledge that you don't have, and you won't get that knowledge just by taking tests. 

Here's what you need to do: go back through the tests you have taken and make a list of the questions you missed. Try to distinguish the ones that were careless errors from the ones you really didn't know how to do (be honest). See if there are any patterns, and see if there are any particular kinds of questions you're consistently missing. When you go back through them, don't just figure out why the right answer is the right answer, but rather try to identify the concept the question is testing.

So for, example, if you missed a subject-verb agreement question on the Writing section because you were thrown off by a prepositional phrase between the subject and the verb, don't just worry about that particular subject and that particular verb. Make sure you know what prepositions are and prepositional phrases are, where they start and where they end, and practice recognizing them. Go get a grammar book -- it doesn't even have to be mine! -- and do a bunch of exercises until you can pick them out automatically. Take a book that has nothing whatsoever to do with the SAT and underline every prepositional phrase that you see. Since subject-verb agreement errors involving prepositional phrases are virtually guaranteed to appear, you stand a much better chance of raising your score if you know unconditionally what a prepositional phrase looks like. And by "unconditionally" I mean that you can recognize one in question 12 of Section 10 after 4.5 hours of test-taking, without even having to think.

If you can identify all the major concepts you're weak on, focus on improving them one at a time , and not take a new full test until you truly feel as though you've mastered something new, you'll be astonished at how long your Blue Book lasts.