It might be better then to look into medical, genetic and environmental aspects, and focus on that instead of trying to find tricks to work harder.

For example, trying to change your environment might help more than busting your a$$. Can you move to a place with better access to education, books, or people with expertise? Can you find places that support some of your needs that enable you to focus on taking a course or other? Can you find programs that can fast track you into a new discipline that's paid for? Etc.

Another example is that if genetics plays a big role, than working hard is counterproductive, instead you'd want to find something that plays to your genetic, whatever that is. Find something that is easy to you, and focus on doing that. Don't waste time trying something you find really hard that you don't have the genetics for.

Now the medical aspects I would say is more in terms of where we invest, instead of paying for self-help pseudo science books and talks. Should we invest in ways to medically address deficiencies in motivation, intelligence, judgement, perception, sleep, etc. This might be a long shot, but I think better understanding the role of genetic, the brain, and all that with regards to accomplishment will help us find actual mechanism that might really work, unlike "hard work".

Personally, I tell people to focus on "easy work". Forget hard work, your goal is to make it so the work you do is as easy as possible. You can achieve that by finding something you have a natural aptitude for, or for which you have the right environment to succeed at. Focus on choosing the right people and place to surround yourself in for whatever the work is you are trying to do. Focus on something that motivates you, and feeds into your reward mechanisms.

Finally, don't consider yourself a failure if you fail, because if you think hard work has nothing to do with it, its just bad luck, so don't be too hard on yourself ;)