it depends...
As a native speaker i find it tough to break habits in verbal, and I'm stuck in the 37-39 range, I can live with this. Once you have your RC strategy down, the only thing left to do is practice. With CR, I haven't found any form of study prep useful... but I tend to miss 1 or 2 of these max, regardless of difficulty. There are many books you can read on SC, and most people feel thats the place to improve your score... When I study for verbal, thats where I focus, but the returns for me are minimal.
Quant is just, easier to improve for me. I've found the journey of trying to get from a 45 to a 50 much easier then breaking into the 40s in verbal. Its all refreshing things you used to know, or proving certain concepts to yourself so they resonate better.
You need to figure out what areas you have the ability to improve on the most, and focus whatever time and energy it takes for you to get the best score possible.