Your current verbal score is 28 (about the 50th percentile) and you want a 35 (about the 75th percentile). That's a BIG leap to make in 3 weeks. Most people would need more time - I just want to warn you about that now. You may have to decide to postpone your test if you really want that score.
There are all kinds of skills that come into play on CR and RC, so I need you to help me narrow things down a little more. Right now, my advice is "everything in the two books" - which is hundreds of pages of stuff!
So let's pinpoint the problems a bit more.
How easy / hard is the reading part of it for you? On CR, are you consistently able to identify conclusions, understand the flow of info, brainstorm assumptions, etc? Or do you struggle with that? On RC, same thing - are you able to identify the overall point? The purpose of each paragraph? The major changes of direction or conflicts?
For the questions, are you able to understand what the question is asking, or do you sometimes struggle with that? Do you know how to identify the different question types, and do you know what you're supposed to be doing for each different type of question?
What about interpreting and choosing from among the answers? Does that give you a lot of trouble? Do you know what kinds of traps tend to exist for the different question types, and how to spot them?
Have you taken an MGMAT test lately? If so, you can use the below article to analyze your results:
http://www.manhattangmat.com/blog/index ... ice-tests/That may help to give you some more insight into what's driving you crazy on these problems, and then you can share that insight here, and we can help you better. :)