TLDR; Do only OG problems, take only official GMATPrep mocks, use TTP.
Resources
1. Target Test Prep - An amazing resource for GMAT preparation. I was initially struggling with the test, especially number theory and sentence correction. I bought this half-way through my 6-month test prep journey after reading all the glowing reviews and it was definitely worth it.
In addition to the high quality materials, here's what I liked the most:
1. No Video Lectures - With video lectures it is very easy to zone out or increase the playback speed to finish it quickly. But with text chapters you are forced to read and understand it. You just have read every word and avoid the urge to skim through. And video solutions to most individual questions are available if you are having trouble.
2. Quizzes - After each lesson, you also have to take chapter quizzes. This is a great way to reinforce learning and find out what you need to study again. Now because I was getting close to my test date, I did skip some of the quizzes when I felt I was comfortable with the material. But in general it's nice to do them all, especially on chapters that you struggle with.
3. Clean User Interface - They have a pleasing and clutter free UI that lets you focus on the content. If the UI is ugly and hard to navigate, you will get fatigued before you even get to the chapter.
2. Official Practice Questions - Obviously this is the gold standard for practice questions. But I would go one step further and say that you should not practice questions from any other source (exceptions: TTP chapter quiz & GMATClub quant quiz). The problem with 3rd party companies is that even if they create a few great questions, they will never have the consistency in quality that official questions do. If you are reviewing and spending time on every error, you should not run out of official questions. You can use the forum quiz feature on GMATClub and filter for 'OG' questions to practice. This way you get great community solutions and an excellent error log.
3. Official Mock Tests - This is the most precious and limited resource for GMAT preparation. There are only 6, and once used they are gone. If you can afford it, you must buy all 4 extra tests (look for coupon codes). Use these tests to understand which sections you want to do first and how you should pace yourself during the exam. Get used to the adaptive format.
DO NOT USE ANY OTHER MOCK TESTS. I've tried them (including MGMAT). There are many poor questions and quality is inconsistent. They probably didn't get the adaptive algorithm right. They will mess up your timing. I cannot stress this one enough.
4. MGMAT book for IR & AWA - The Manhattan Prep strategy guides are decent, especially if you can find them 2nd hand. Good complement to the TTP course, but not necessary. However, for IR and AWA i depended on these books, and I think the material was very good.
Verbal: CR & RC
Personally, I feel that most advice found online for CR & RC is useless. I don't think it's a good use of time to learn so many different question types. Instead, just practice the official questions. Spend time understanding it. If you disagree with the official solution even after spending a lot of time analyzing it, move on for the time being and revisit it in a week.
Cricital Reasoning - Don't learn the question types. But do understand the breakdown of the structure of an argument and get good at identifying parts of an argument as you read it (premise/ conclusion/ other information). Also get used to identifying difference between things that are necessary and sufficient, and things that must be true, must be false, provide weak support, provide strong / direct support. Once you get this, you can use PoE to get to the answer fast. No need for question types and strategies.
Reading Comprehension - For me this one came down to being curious about and interested in the passage. I took my sweet time reading and understanding passages, often 1 - 1.5 mins more than what is commonly recommended. Sucks when there are fewer questions from the passage, but beats wasting time going back & forth or getting it wrong. After reading the passage, use process of elimiantion for each question and reference back to passage as needed. Again, most "strategies" are useless except this one:
Show Spoiler
Verbal: SC
Most of my verbal errors were on Sentence Correction. I hate this section. I know these are supposed to be meaning based, but on the more difficult questions it always came down to grammar. It was just annoying to have to learn so many grammar rules (all of which have exceptions) as a non-native speaker. I didn’t want to learn the meaning of an infinitive or gerund and have to identify them in every problem (still don’t know what they mean). I decided that the best course of action was to practice and build intuition. TTP text and practicing official questions eventually made me better at SC. Take notes as you go through TTP, especially when you get something wrong in the lesson review questions.
Quant
I won't preach too much because many people get a Q50 or Q51 and I did not. TTP chapters were very useful, especially number theory. Strategies from OG, TTP and even MGMAT were useful. But those math revolution ivy method or whatever sounds like a bunch of BS to me. Sorry. TTP also hosts 1 hour sessions on YouTube going through difficult questions, I think they are great. Watching someone solve questions live is very helpful. Also there's a guy on youtube called Avi Gutman, videos of him solving problems are very very high quality and helpful. Lastly, the GMATClub quant pack is pretty good. I know i said official questions only, but if you are looking for challenging questions that reinforce your concepts, go for the GMATClub questions. Just don't let them effect your timing (they are not normal GMAT difficulty).
Other Notes
1. Every guide has a section dedicated to mindfulness, 'zen', etc. I'm sorry but are you really going to change your entire lifestyle? You still have a job and other responsibilities. I don't think these are very useful. And I refuse to give up coffee
. 2. That random easy question you saw was an experimental question. It was not there because you got something wrong.
3. TTP is expensive so don't buy it and just sit on it. It makes tracking progress very easy so use it as much as you can. Build your own chapter tests if you need to.
