Training hard is NOT enough!
Many young talented chess players over the years told me that they are training very hard but they were not making enough progress.
Training hard alone is NOT enough! One must also learn the right things the right way. After a certain level, general training alone is simply not enough.
Players MUST be able to OBJECTIVELY assess their strengths and weaknesses. Only then they can know what to focus on. This is why it is critically important to have the right coach/advisor.
Once players are able to pinpoint the problems, they must also be willing to improve and make changes. Too many choose to stick to their comfort zone and are afraid to change because they are afraid to lose rating points.
No pain, no gain, no risk, no reward!