Changing tactics when natural ability is reached? Question 
What habits and attitudes need to change when one hits the upper bounds of natural ability? This is the situation where you can no longer increase your rate of advancement. In effect your effort is "bounded from above". I am thinking primarily about research and learning from a student's perspective but I am sure this problem is common to everyone eventually. There must be some limit at which even the greatest stop accelerating. Given that this barrier has existed for a long time and affects every human that ever lived, there must be structual approaches to overcoming exhaustion of the lowhanging fruit. What are proven methods to continue improvement, or, failing that, hug the limit of natural ability as tightly as possible? Similarly to compound interest, if you underperform by 3% every year, then in 24 years you will be half the man you could have been.

The answer from Ben succiently explains this idea in the work equation:

work = (work rate)*(hours worked)

Assume that for whatever reason the goal is to maximize the work. If one can no longer increase the hours worked, what are strategies to increase the work rate?
 What are new ways of thinking that can keep one at maximum possible performance? Are there ways of structuring your time that you have found that just work. What really helped you in staring down your own limitations?

My Motivation: 


   I have been fighting this ceiling for several months now, and I am getting   >! to a hard physcial limit. I am at a barely ranked school and still have the  dream of significant contributions to my field. Realistically this dream requires me to perform on the level of students at top universities. My first strategy was to just put in more time than the students who do better than me. It worked to beat the undergraduates here who spend 40% of their time on extra curriculars and social lives. However the graduate students are much more disciplined and working harder than their 80-100 hrs/wk is of much greater difficulty. To further compound the problem, we are nowhere near the quality of the top schools, so I fear beating the best grad student in my department would be equivalent to a freshman at T1 school.

 I only started to work systematically when I started university, and have now developed a strong work ethic. I am at the point where I have eliminated everything else in my life except classwork and research projects. There is no longer any significant reservoir of time I can tap to make progress. I likely can obtain about 10 more hours a week if I mange to crack down on the instances where I am actually unproductive. This is my budget for improvement. Others may have more time available which is why I am not asking about quick hacks (although quick hacks would help me more).


Note:I am just beginging my academic career, but I am really concerned about not being able accomplish my goals. If you understand what I am getting at please feel free to edit to make the key idea more clear. There has to be a way using logical frameworks to minimize the inherent limitations of whatever body you are stuck with. I am not looking for a "self-help", "positve thinking" style answer. I am looking for methods that you, SE.Academia, as men of science and reason, find that work.

edit 
I have put the motivation in spoilers because it is not important for answering the question I want to ask (should I just remove it?). Some answers are addressing my specific situation which I think is not the purpose of this site. We are supposed to ask general questions that can apply to others, not just advice threads.
"I am at the point where I have eliminated everything else in my life except classwork and research projects."

That is likely to be counter-productive. You need to leave room in your life for inspiration to strike, not just perspiration. Go for a walk. Take up a hobby that does not require total concentration. You may be limiting yourself by not allowing enough time for rest and relaxation.

I know I am much more likely to get a creative idea for solving a problem doing something else, rather than staring at it, once I have the background firmly in my mind.