About half an hour ago, I responded to another post that asked the exact same question. This is very common - you are not alone!
Basically, your brain is so overloaded with newly-learned stuff that it's taking huge mental energy to remember everything and try to apply it efficiently. This tends to mess up your process for the second test. Most people will have way too many instances of "But I studied this! I should know how to do it, now!" which will lead you to use too much mental energy and time, causing careless mistakes and a drop in score. Do this too much during quant and you'll be much more tired out during verbal, which will lead to the same thing.
Did you feel this stuff during the test:
http://www.manhattangmat.com/blog/index ... you-crazy/Now, on to your question about verbal. Was your initial verbal score high enough that you wouldn't want it to be any better? If you're already scoring in the 90th+ percentile, then no, don't learn our stuff. Just keep doing what you're doing. :)
But if you want to lift your verbal score, you're going to have to study something. It may be the case that you pick and choose - maybe you already have a great grammar ear and it just messes you up to try to articulate the rules officially. If it's the case that you almost always got these right, then keep doing what you're doing. (And when you do get something wrong, go learn that particular rule and also figure out how you fell into the trap of picking the wrong answer.)
If you'd like to get more specific advice out of the test results, first, read these two articles:
https://www.manhattangmat.com/blog/inde ... lly-tests/http://www.manhattangmat.com/blog/index ... -the-gmat/Then, use the below to analyze your most recent MGMAT CAT (this should take you a minimum of 1 hour):
http://tinyurl.com/analyzeyourcatsFigure out your strengths and weaknesses as well as what you think you should do based on that analysis. Then come back here and tell us; we'll tell you whether we agree and advise you further. (Note: do share an analysis with us, not just the raw data. Part of getting better is developing your ability to analyze your results - figure out what they mean and what you think you should do about them!)