I struggled mightily with Quant throughout my struggles and it was mainly because I really didn't understand number properties. Questions that seemed so difficult could be answered by acquiring at least a decent grasp of the most fundamental aspects of number properties. Once you understand the principals of number properties it makes everything else much easier.
Also, do the
GMAT Club Tests because it's well worth the money. The questions are in the style of the actual GMAT, but are a lot harder and prepare you well for the real day. I started off at around 37Q a couple of months ago, and I took my GMAT yesterday and scored a 47Q. The jump can be made by really understanding number properties (and luckily for me avoiding combinatorics and geometry on the real test).
The whole
Manhattan GMAT set is very helpful along with the
GMAT Club Tests...those are pretty much all I used to study and I pulled off a 710 (and I'm by no means a math whiz in any sense).
As far as Verbal goes, I'm not really sure how to help you. I'm amazed that all of the non-native speakers on here do so well on Verbal. It's extremely difficult for me, so I can't even imagine how they've managed to master it. Again, I used the Manhattan set and really just focused on the strategies they teach you. Don't try to bring real world information into questions...just read the conclusion and try to take logical steps on your way to the answers.