We should not seek to tune out the realists' whines or taunts, as they may provide good instruction.
To inspire a singularity of focus, a challenge must be important to you and it must be something you feel you should do now in this moment. If it's trivial or not time-bound, you won't engage. So in selecting your next challenge in life, choose one that is meaningful and will demand your complete concentration.
The first thing successful people do is view failure as a positive signal to success.
To me, meditation is simply silencing or focusing the mind.