Hi aniriddha,
As Scott mentioned - improving by 7 points could be a tall order but let us try!
Forget focussing on the number of mistakes. The algorithm is such that you might make similar NUMBER of mistakes but get a higher score - because the algorithm also takes the POSITION of your mistakes into consideration. The fact is you are not able to get beyond a particular level (say V 35) the moment GMAT starts throwing questions of a higher difficulty level you are making mistakes i.e. you are not able to solve with your current ability /level.
Here are the basic categories I want you to focus on:
#1) You are probably good at certain topics and perhaps suck at a few. Over the next few days - focus exclusively on the areas that you are not comfortable with. For example, let us say in SC you end up having problems with superficial parallelism then try to solve questions only on that topic. Unless you build your muscle in that area - GMAT is not going to be kind to you. So every time you are making the same mistake - you are getting pulled down. You may be KingKong when it comes to CR but it doesn't matter because SC Parallelism is pulling you down. Get the idea?
#2) Now let us look at the application of the concepts you have studied. How much time are you taking to read the passage? How are you eliminating the options in CR? How are you looking at the intent before applying grammar to SC? These are the things you will face at V35+ - things you don't necessarily need to worry too much about at a V30 level. In my opinion, you need to really relook this part - it is what is stopping you from breaching the 35 point barrier.
#3) Okay let us take the last thing - how are you performing on the actual test? Are you able to do the context switching among the three topics? Are you able to manage time well? How well do you get when you get stuck? Is it an educated guess or do you also resort to blind guessing? This is the OPTIMIZATION bit - that is - with your current level can you squeeze out a few extra points (believe me - it is possible).
I know this is a LOT for you to chew in the next few days but I am sure you will get some clarity. I am giving you some resources that might help:
Webinar on how to score V 40+
https://www.youtube.com/watch?v=oeKpK1VM2KoWebinar on how to score Q 51
https://www.youtube.com/watch?v=pzI9DzxN0lE5 Strategies for retakers
https://www.youtube.com/watch?v=PjJ_AyeL5243 Things to learn from a GMAT 760-scorer
https://www.youtube.com/watch?v=EyVmhFlliuoWe also provide specific personal tutoring for students who are stuck and not able to get their scores up:
https://www.crackverbal.com/gmat/personal-tutoring/Hope this helps,
Arun