Some GMAT questions have tricky wording. Somethings that help me include:
(1) Writing down all the given information. Just looking at a problem and rereading it 3+ times will waste time. Start getting your pen moving and as you actually write down the numbers you may find certain relationships within the numbers that will help you arrive at the final answer.
(2) The
MGMAT Quant Guides have a lot of formulas/techniques per chapter. For example, in Word Translation, they give a simple formula for average. If you see a problem asking for average, immediately write down the formula and try to fill in as much of the information you can. Writing down the formula will help things click much faster.
(3) A lot of the
OG problems follow a certain pattern and test certain concepts over and over again, only after doing a lot of practice will you grasp these patterns.
(4) As you said, some of the explanations will show you a different way to attack the problem then how you did. I would put a lot of time learning the different ways to attack a single problem. Having multiple techniques on hand will help you grasp and start more problems quickly.