Hi Nums99,
SCs are 'technical' in nature (similar to how Geometry questions require knowledge of formulas) - and while you can learn a number of different patterns in how GMAT SCs are written, you still need to know the grammar/idiom rules really well (and be able to spot when they apply) to score higher in this category. Thankfully, there aren't actually that many rules to learn.
While the ESR doesn’t provide a lot of information, there are usually a few data points that we can use to define what went wrong on Test Day (and what you should work on to score higher). Since you purchased the ESR for your recent attempt, then I'll be happy to analyze it for you. If you would rather not post it publicly, then you can feel free to PM me directly.
Before I can offer you any additional advice for your studies, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) How long have you studied in total? Over the last 3 months, how many hours did you typically study each week?
2) What study materials have you used over the course of ALL of your studies?
3) On what dates (or approximate dates) did you take EACH of your CATs/mocks and how did you score on EACH (including the Quant and Verbal Scaled Scores for EACH)?
Goals:
4) Is your overall goal score still 750?
5) When are you planning to apply to Business School and what Schools are you planning to apply to? If it's sometime soon, then what specific application deadlines are you facing?
GMAT assassins aren't born, they're made,
Rich