To move verbal score into 40s, you can follow this…
1) Analyze the reason for below 40 score. Is there a weak area (like you mentioned SC) or you feel low energy/concentration by the time you reach verbal section after completing AWA and quant section. One way to identify this will be to practice 20 SC questions (in 25 minutes) at a time from 1000 series. Your verbal is weak if you have more than 3 wrong (out of 20) in SC. Similar tests you can do for CR and RC.
2) If SC is weak, best source to learn concepts, as mentioned by Kevin, is Manhattan SC book. For practice, OG 11 and 1000 series are the best source. Explanations in OG 11 are very good and you will learn many good concepts from them.
3) For CR, I found 1000 series as the best source for practice.
4) For maintaining energy/concentration level, you will have to find what works best for you. Select the food which you need to take during breaks to maintain right glucose level (for maximum brain activity) throughout exam duration. Similarly have a strategy for getting good night sleep on the night before exam. I read in other forums that some people take Nyquil to have good night sleep before exam. So you can find what works best for you.
Apart from that, I will say that try to move your score in quant also to 50-51 range. Try to solve all questions posted on Math thread and that WILL help you move into 700+ region.