Because the GMAT is an adaptive test, it's not about the # correct. Someone with a 20 might not miss many more than someone with a 30. It's all about the difficulty of the problems you're able to get right. One important issue is timing--make sure that you're letting hard problems go when needed, so that you don't end up rushed or (worst of all) time out at the end.
If RC is tough, make sure your initial read is really strong. Do you know what the author's point is, and what each paragraph is doing in the passage? When you get a specific question, do you know where to look to find the answer, and do you make sure to look back for support instead of relying on memory? Are you good at inferences, including Draw a Conclusion questions in CR?
If not, that may be undermining your RC performance. For many people, improving in verbal is all about learning what can and cannot be inferred from a given set of information. Below are two other RC posts I was just looking back on. Maybe you'll find them useful.review-rc-passage-mistakes-112792.html#p913356reading-comprehension-time-management-121907.html
Those are my 2 major issues in RC. I usually have a problem to locate the detail once I've read the passage and inference questions are my nemesis lol but I've been getting better at it. Thanks for the tips!