Improving my score from 550 to 600+

Hello, Claudio97. Sorry to hear about your uphill battle with Quant, but it is one that all GMAT™ test-takers experience in one area or another. Since you broached the topic, your private lessons twice a week should be enough, with the right tutor or teacher, to help you get to where you would like to be. But if you are just going over questions, you will not likely make as much progress as you could if you were systematically going through each math topic and then applying such conceptual knowledge to high-quality GMAT™ practice problems. Many online learning modules, such as those by EMPOWERgmat, Math Revolution, or Target Test Prep, offer cheaper alternatives to the services offered by tutors, with the advantage of being accessible at any time. Please do not get me wrong: private tutoring can be an excellent avenue to pursue for eventual success, but I also know, as a private tutor, that such services can be expensive, and if you can make improvements in your conceptual knowledge on your own and then start to work with a GMAT™ tutor to further refine your test-specific technique, you will likely strike a better balance. (You want to get what you pay for with a tutor, and perhaps time spent either covering question after question or reviewing concept after concept could be time and money better spent elsewhere.)

All the best to you. Keep studying!

- Andrew

So, first things first. I'd like to thank everyone for their time.
Are you therefore, suggesting that I should spend more time on theory now instead of focusing on heavy simulations (just on Quant), for example: review of theory, 2/3 hours a day and maybe eventually a 10/20 questions simulation?
I am currently revising (theory only) from KAPLAN Prep Plus 2020. But I could also sign up in one of the portals you mentioned in your comment MentorTutoring. What do you guys think?
Because I don't really have a topic I'm struggling with, I just want to raise the level at this point by trying to get most of the Hard and Medium-type of questions right.

I appreciate the mention, Claudio97. It gets my attention, and I feel compelled to respond. To be sure, I myself enjoy practicing questions way more than delving into theory, but at the same time, I can appreciate that a solid conceptual knowledge is required to score well on the Quant section, so I think it will be important for you to find the right mix. Perhaps if you found a certain topic less intuitive--combinatorics is a popular one in this category--you could ask your tutor about that topic the next time you met. Or perhaps you could find five questions you had not understood that all fell within a certain branch of mathematics--say, geometry--and center a lesson on that topic. Make sure you keep an error log so that you are not just blundering through questions. I just want to spare you the agony of thinking that a few good books and regular meetings with a tutor will automatically lead you to the score you want to achieve. Learning does not work that way, nor does tutoring. I love practice sets of questions in 10/20 sets. I would not discourage you from attempting such sets. However, you want to be sure not to exhaust valuable material, such as the questions in the OG, before you know what you are doing. Treat any official material as gold, something to be taken in in increments, not something to simply blow through and hope that you get better along the way. If you arrange practice sets of questions, then see if you hit maybe a 90 percent accuracy (or greater) on Easy questions, an 80 percent accuracy on Medium questions, and a 70 percent accuracy on Hard questions, but do not allow yourself to graduate from any Easy set to a Medium one until you are consistently achieving your mark. In this manner, you will be going through practice questions with much more of a purpose. In short, I would recommend a theoretical approach more in the beginning, but once you feel comfortable with the theory, you will need to practice on high-quality questions to demonstrate your knowledge, and you can always refine your approach during this process. My online module recommendation was based on two considerations: 1) relative affordability and 2) high success rates among GMAT Club members who have used such avenues to prepare for the test.

Keep bouncing ideas off the community. No one has all the answers, but when many people start to offer you similar advice, the wisdom of the community typically holds true. Good luck.

- Andrew