First, do you actually need a higher score or do you just want one?
When considering only the quant section, a score of 48-49 in quant is good enough for any school. The schools also, of course, consider your overall score, so if you need to lift that score and are much better at quant than verbal, then you may try to lift your overall score by continuing to improve quant even though you already have a very high score.
If your overall score is also already good, though, and you are just trying to get a higher quant score because the percentiles are making you think that 48-49 is low, then you don't need to do that - that is a high quant score, not a low one.
Next, the higher you go, the harder it is to go even higher, of course. The first thing that you want to examine is all of the "low-hanging fruit": the things that you could fix or improve relatively easily. The two biggest areas are careless mistakes and timing.
Here's how to minimize careless mistakes:
http://www.manhattangmat.com/blog/2012/ ... -the-gmat/What timing issues are you having? Everyone has at least some timing issues. If you aren't sure--or think you don't have any--then use the below article to analyze your most recent MGMAT CATs and tell me what your timing issues are:
http://tinyurl.com/analyzeyourcatsHere's what you can do to start to remedy any timing issues:
http://www.manhattangmat.com/blog/2013/ ... -to-do-it/http://tinyurl.com/GMATTimeManagementFinally, if you need to push your skill level even higher (ie, if the above steps aren't enough), then I have two recommendations.
First, make sure that your mindset matches this:
http://tinyurl.com/executivereasoningAnd your study habits follow this:
http://tinyurl.com/2ndlevelofgmatSecond, you may want to consider getting our Advanced Quant strategy guide. It's designed for people who are at your current level and want to lift to the 50-51 range. (If you do this, get the book soon and you will have time to work through it. Don't wait until just a couple of weeks before the test.)