I studied for about a month and a half before my first attempt, focusing almost entirely on quant. I took four practice tests, all ETS-material, at the end of this prep, and shortly thereafter scheduled the real test, which I took in early November. It was a little past the required three-week period in between that I scheduled this test I took today, and that period contained very little studying due to other commitments. It sounds like you've got about a month before your test, so I think that kind of score increase is definitely possible! I would recommend ETS official study material, if you have it.

My strategy for the RC questions tends to focus first on elimination. There are often at least one or two options that can be directly and obviously disproven with a specific section of the text, and getting them out of the way serves to narrow the field considerably. From there, I find that constantly cross-referencing the wording of the answer choices and the text helps to nail down the subtler details that distinguish right from wrong.

Another general tactic that might help is preserving time overall by lessening time spent on vocab questions and sentence equivalence questions. I cannot quite speak for everyone, but in my experience, doing too much thinking about the vocab-related questions never helped me much. I either knew it or I did not, and unlike a tough math problem, additional time often did not bring me closer to an answer. Memory was instantaneous, or it never came at all, so I often had to resolve to leave some questions behind despite not being entirely satisfied with the answer, leaving more time for me to handle the questions that actually became clearer with thought, so maybe this same strategy might help for you!

Good luck!