Hi kimkm509,
To improve your verbal score, it may be a good idea to concentrate on learning/practicing one section at a time: reading comprehension, sentence correction, or critical reasoning. Have you been able to study in this way?
For example, when learning about critical reasoning - your weakest topic according to your ESR- attempt to master all aspects of critical reasoning before moving on to another section. Follow up your learning with focused critical reasoning practice, so you can determine your specific weaknesses within that topic. For example, if you continually have trouble with strengthening arguments based on scientific evidence, you will want to identify and overcome that difficulty. You should follow a similar routine for sentence correction and reading comprehension.
Also, to help improve your reading comprehension, I recommend reading publications such as the Economist, the New Yorker, Scientific American, or the Smithsonian so you can get used to reading and analyzing long, sophisticated passages that are well-written.
To master sentence correction you must become proficient in the use of grammar rules (parallelism, subject-verb agreement, comparisons, pronouns, etc.) and accepted English usage. Concentrate on one topic at a time, such as modification, and practice with as many realistic modification questions as you can find. Only after you feel confident with modification should you move to the next topic. In addition to your dedicated study, notice grammar and usage in your everyday life. When you read emails, articles, or even blog posts, pay attention to sentence structure, subject-verb agreement, the use of pronouns, and even punctuation. Use proper grammar in your everyday writing as well. Have you put parallel ideas into parallel constructions? Do all of your pronouns agree with their antecedents? The more you reinforce your study with related activity outside of your study, the greater the likelihood you will master the topics, and have fun doing so!
If you have any further questions, feel free to reach out!