eugenebhatt
Thanks Arun for your suggestions.
1. In quant, I usually have problems in DS. Most of my mistakes in practice tests were in DS. But I was surprised to find that DS on the actual exam was not that tricky. I failed to recognize 2-3 pattern questions in PS towards the end of the quant section and spent more time on these questions. Because of this I had to guess 2-3 questions which were wrong (now that I solved them at home). On reflection, I approached DS with more "respect" on the exam because I was expecting them to be more harder than they actually were and relaxed a bit for PS questions.
2. In verbal, I started slow cos I dint want to make many mistakes in the first few questions. As I mentioned, SC is my strong suit but I got a few awkward questions in between where I spent more time. I feel that I did not "attack" the verbal section and was relaxed when approaching the first 20 questions. I had around 34-35 minutes left for the remaining 21-22 questions. I did not get a chance to prethink answers on CRs. I just tried to eliminate all the out of scope/opposite/extreme answers and pick one which I thought was best. For RCs, retention was a problem.
For quant, the problem at a 50-raw score level in DS is that it pretty much becomes a question of application and not so much knowing your concepts. Also you said "DS on the actual exam was not that tricky". The trick with tricky questions is PRECISELY that - they don't look tricky. Almost paradoxical

For verbal, I have a few suggestions for you:
1. I am not sure how spending MORE time can help increase your accuracy. I mean, yes maybe for a few questions but overall time and accuracy are not directly proportional i.e. the more time I spend per question, the greater my probability of getting it right. So you need to get better at guessing. Guessing not when you are stuck and have spent 2minutes but guessing early on - say 30seconds into the question on whether it is worth pursuing it.
2. Also 34-35minutes for 21-22 questions means you had roughly 95seconds per question - it can be tough getting out of that situation since CR would consume more than that. (Again a bit paradoxical that you can solve faster because not being able to do it fast is what got you in this position to begin with!) so you have to arrest the problem before that. Here is a recommended approach: Try to cut the 75minutes into 5 mini-tests of 15minutes each and try to solve 7 questions in Quant and 8 questions in Verbal in these mini-tests. Even if you get around 5 questions correct in each of these mini-tests you can potentially hit a 750+ score.
3. I am not sure of the techniques you have mentioned but here is some food for thought - any technique that doesn't help you on the day of the test is a technique not worth using while you practice. So try to take a step back and see if (a) you are using the techniques incorrectly (b) that technique works for YOU. In either case it would require a change in your approach.
Hope this helps,
Arun