Background
Registered for GMAT on 23 Dec 2014. Scored 690 (Q41, V44, IR 7, AWA 5). Rescheduled for next earliest opportunity on 23 Jan 2015, scored 740 (Q49, V41, IR 8, AWA 5.5)
The Experience
On my first attempt, I felt really confident. I thought I had all the concepts for Quant drilled into my head. No small thanks to my instructors at Prep Zone Singapore.
A week or so before, I had spoken to an old friend who had scored very well. He gave me a piece of advice - to beware the first few Quant questions. Unfortunately, that proved to be my undoing. I spent about 10 minutes on a very simple first question that I had misinterpreted. The rest was a disaster. Lost points on questions I knew I could solve because I didn't have enough time to work through them properly. Promptly re-registered.
Cue an extremely busy December and January. I had no time to work on the GMAT, except for the week leading up to the second attempt. I remember spending two four-hour sessions in preparation. That said, I knew that Q41 was not my true level. I was still confident.
On the day of my second attempt, I was extremely disciplined and paid a lot of attention to the clock. When faced with very difficult questions, I made my best possible guess and moved on. Ironically, I still felt some unease, as the Quant questions felt too simple. I thought I had not hit the higher level questions. Test fatigue set in, and I started breezing through my Verbal section, which explains the drop in score.
Key Takeaways
Really not much here, except that time management really is crucial. Even for the first few questions, if you get stumped, try your best to work your way up again. Don't get too fixated on getting any one question correct. The test works best when you're able to work through questions of varying difficulty, allowing its algorithm to find out your true level.
Looking back beyond my first attempt, I learnt that pattern recognition is extremely important. It's one thing to get the concepts of square roots, perfect squares, primes, factors and divisibility, geometry, etc all in your head. It's another to recognise what form of arithmetic manipulation the question is requiring of you. Practice a lot, not because practice will make you smarter. Rather, practice allows you to form quick judgements of the question type. From there, it's an easy breeze to start breaking down the question into the topical areas listed above.
Besides that, memorise the quick fixes that allow you to work through computations really quickly, e.g. the 1-1-\(\sqrt{2}\) right triangle, 1-\(\sqrt{3}\)-2 right triangle, prime factorisation techniques. Speaking anecdotally, I found that lots of questions had to do with prime factorisation and divisibility. Don't get too caught up with permutations and combinations. From my own experience, they are hard (if you don't get the concepts right), but they don't appear a lot. Focus on number properties.
Can't say much about Verbal. Although I spent time drilling the concepts, they came pretty naturally to me so no tips to offer. AWA and IR - did not prepare at all, except on practice CAT.
Hopefully, this has been helpful. Writing this is mostly catharsis, as I sit waiting to hear news from the schools I've applied to.