My background may be different from other people on the forum because I am actually applying for a PhD in business, not a MBA. I already have a MSc in Business. Most PhD programs do not publish an 'average' GMAT score but I imagine that a score of 750 is helpful in getting admission and funding. Although my native language is not enlish, I read from the good newspapers like the NYtimes on a daily basis.
I started preparation 3 months ago and began by downloading GMAT prep software and taking the first practice test (scored 670 (Q42, V40)). I was quite happy with the verbal score so most of my prep efforts were on Quant. I had huge issues in time management in Math.
Sorry I can't post URLs but you should be able to look up the titles listed below:
Math1.
Manhattan GMAT manuals (Number Theory, FDP, Geometry, Word Translations, etc)
2. GMAT Club Math book v3 (Good for formulas)
3. Manhattan Advanced Quant (fantastic for strategies in 700+ DS especially if time is short)
4. Official Guide 12th edition (I was getting most of the 'hard' questions right so I abandoned this book and only completed 25% of it)
Verbal1. Kaplan 800
Like I said, I scored pretty well in the very first test so I didn't study this much. But a quick few tips:
SC: There are only a few rules being tested here and these are discussed in most of the manuals (Manhattan, Kaplan, etc). I don't think anyone should waste time memorizing 100+ idiom lists and should focus on learning and applying the basic grammar rules
CR: I LOVE THESE QUESTIONS! Kaplan 800 has some great CR questions.
RC: Again Kaplan800 has great questions.
Practice tests1.
Manhattan GMAT Tests - I scored (650, 700, 720). I think the math in these tests is harder than the actual tests.
2. GMAT Prep - Great resource but you only have 2 tests. I tried to 'reset' the question base but I noticed that most of the questions would repeat themselves. I took one test before preparation (scored 670) and took one test towards the very end (scored 770).
3. I couldn't afford premium tests available here ($75 really?) so I just used the free forum questions
Lots and lots of practiceA lot of people think that they need to learn a ton of strategies and formulas in Math. I think there are a few basic formulas/strategies that can be learned in 2-3 weeks and then it is all about practice on harder and harder questions. I practiced 20-30 a day for 3 months from this forum.
Time ManagementI had to develop the 'internal clock' in my head that rings after every 1.5 mins. When it 'rings' I had to consider whether to:
1. Make an educated guess. I became a pro at guessing in DS questions
2. Change strategies and try another approach
Good luck everyone!