Do you think it is wise to email those in the admissions committee to find out what my chances are and if there is any way to improve, or maybe find out what they're looking for in an applicant, etc...
What kind of program are you applying to? I think in general the answer is no. It's usually not too hard to figure out what they're looking for in an applicant anyway: good grades, good letters of recommendation, some research experience... if you're applying to a very prestigious program replace good with "excellent" and, depending on the field, throw in a conference paper and/or peer-reviewed publication. For the statement of purpose, be specific enough for the school to know you looked at their website and have a clue what you're interested in, but not so specific that it looks like you're going to be stranded if one member of the faculty leaves. In some fields, you should be in communication with a potential adviser ahead of time, in others you should avoid contacting faculty.
In general, you should ask the people who write your letters of recommendation to assess your chances and tell you about the norm in your field. They should be familiar with the field you're applying to and by virtue of having agreed to write a letter for you also care enough to help you.
There's generally nothing you can do immediately before a deadline to make your application more appealing. The best use of this time may be to go to your school's writing center (if available) and have them look at your statement of purpose. Next, walk over to the career center and have them look at your resume/CV and make sure everything you did is on there and phrased/formatted appropriately. There are plenty of things, particularly with CVs that are easy to fix and can only benefit your application. If it turns out you don't have enough research experience, on the other hand, or your GPA is too low, you're not going to remedy that by the time the school makes its decision. Similarly with the GRE, but schools generally publish what their median scores are, so as long as you are above that it shouldn't be an issue. (If you are below, it's not necessarily a concern either - half the people who get accepted are so by definition. But it probably means you have a smaller error tolerance on other items.)
By the way: for rolling admissions, I hope you applied well in advance of the deadline? I think, generally speaking, it's easier to get in the earlier you apply.
Best of luck!
