One thing you could do to improve your RC accuracy is to spend as long as you have to on each 700-level question to fully analyze each choice and get the question correct. In other words, even if you have to spend 10 minutes or more per question, do whatever you have to in order to get 90+ percent of the questions correct.
By practicing in this way, you'll give yourself time to learn how to get 700-level questions correct more consistently.
Then, once you're getting them correct close to 100 percent of the time, work on reducing the time you spend on each question by looking for ways to answer them more efficiently. Also, by practicing untimed, you'll develop stronger skills that will enable you to answer the questions faster.
For some ideas on how to answer verbal questions faster and complete the section on time, see this post.
How to Get Faster at GMAT Verbal