if you are looking for a high scores of Q49+, then an essential skill on 90% of the Quant problems is to know within a few seconds of reading a question, the steps you need to take to solve the question.
A good analogy will be swimming, if you have practiced your strokes enough number of times & built that confidence, your body will not think but rather it will act.
So the key is "Act not think"
This will require
- a comfort level with the variety of problems tested on the GMAT
- a fair amount of practice solving the problems on the most common concepts tested on the GMAT.
- a fair amount of practice testing your strategy to solve each type of problem
- building that confidence level, of knowing that the steps you took have led you to nothing but the correct answer. This is very true for DS questions, as you should not have any doubt, while choosing the answer choice.
Now you can choose to have multiple strategies, but you should also have one master strategy, which you know for sure that it will lead to right answer, & accessory strategies (if there are any) as back up, in case a tricky question comes up.
Even if you are not aiming to score high on Quant, still honing your Strengths & overcoming weaknesses with the above process, will ensure in achieving your goal.
Hope that helps!!
Cheers,
GyM
P.s. - i guess your query was pertaining to only Quant problems