Hi vincio998,
The good news is that V40 is not a bad start! To improve your verbal score to a higher level, you have to go through GMAT verbal carefully to find your exact weaknesses, fill gaps in your knowledge, and strengthen your skills. The overall process will be to find weaker areas, learn all about how to answer questions of types that you aren't that comfortable with now, and do dozens of practice questions category by category, basically driving your score up point by point.
For example, assume you begin studying Critical Reasoning. Your first goal is to master the individual Critical Reasoning topics: Strengthen the Argument, Weaken the Argument, Resolve the Paradox, etc. As you go through the questions, do a thorough analysis of each question that you don't get correct. If you missed a Weaken question, ask yourself why you didn't get it right. Did you make a careless mistake? Did you not recognize what the question was asking? Did you skip over a key detail in an answer choice? Getting GMAT verbal questions right is a matter of what you know, what you see, and what you do. So, any time that you don't get one right, you can seek to identify what you would have had to know in order to get the right answer, what you had to see that you didn't see, and what you could have done differently to arrive at the correct answer.
Each time you strengthen your understanding of a topic and your skill in answering questions of a particular type, you increase your odds of hitting your score goal. You know that there are types of questions that you are happy to see and types that you would rather not see and that there are types questions that take you a long time to answer correctly. Learn to more effectively answer the types of questions that you would rather not see, and make them into your favorite types. Learn to efficiently answer questions that currently take you five minutes to answer. By finding, say, a dozen weaker quant areas and turning them into strong areas, you will make great progress toward hitting your quant score goal. If a dozen areas turn out not to be enough, make some more areas stronger.
When you do dozens of questions of the same type one after the other, you learn just what it takes to get questions of that type correct consistently. If you aren't getting close to 90 percent of the questions of a certain type correct, go back and seek to better understand how that type of question works, and then do more questions of that type until you get to at least around 90 percent accuracy in your training. If you get 100 percent of some sets correct, even better.
So, work on accuracy and generally finding correct answers, work on specific weaker areas one by one to make them strong areas, and, when you take a practice GMAT or the real thing, take all the time per question available to do your absolute best to get right answers consistently.
The GMAT is essentially a game of seeing how many right answers you can get in the time allotted. Approach the test with that conception in mind, and focus intently on the question in front of you with one goal in mind: getting a CORRECT answer.
You also may find it helpful to read my article for more information regarding
how to score a 700+ on the GMAT.
Feel free to reach out with questions.
Good luck!