A bottleneck is simply a limiting factor. What’s holding back your performance? This isn’t always identifiable, and it may not be easily fixable, either. But if progress isn’t being made, it’s important to figure out where the bottleneck is, so that actions can be targeted. The answer for many is simply “work harder,” but a lot of work at random isn’t going to fix specific problems. Figure out what the issue is, and aim at fixing it with the right work.
Apply this idea to all aspects – nutrition, sleep, recovery, training, you name it. Not eating the way you should? Why not? What can you do to fix it? Not sleeping enough? What can you do to fix it? And on down the list.
Sometimes it’s going to result in answers you don’t want to hear or changes you don’t want to make. Then the question to be asked is, how badly do you want the result? I’m not saying you should necessarily re-organize your whole life to achieve it, but if you’re not willing to make some sacrifices to achieve it, then most likely you don’t want it too badly anyway.