Hailed as one of the key reasons behind the success of British Cycling Marginal Gains is an important principle all athletes, teams and organisations should take note of. In the graph above if you take two people who make a commitment to a new goal - lets say running a marathon. In the beginning while one sits on the couch and watches TV (normal behaviour) and the other person goes for a short run 3 x per week (new behaviour) in the beginning the distance between them is very small (almost unnoticeable).
However as time passes and they both continue in this vein the gaps widens and so do the results. One has accepted the changes and the new paradigm while one has rejected it. Over time this 1% gain (creep) begins to make a big difference in their attitude, their results and even how they look and feel.. This along with paying attention to the smallest details (like taking your own pillow when competing or training abroad) to seek even a 1% (or even smaller) gain is the philosophy behind marginal gains.
For more info on this performance principle check out this short video with Sir David Brailsford (who popularised this the theory of marginal gains as the High Performance Director of British Cycling) https://www.youtube.com/watch?v=NQxYlu12ji8
Keep looking for those gains.