The ability to concentrate is both the the key to martial arts success and is developed by proper martial arts practice. Not every school systematically teaches how to successfully concentrate. We do it through the practice of meditation.
Find a quiet place where you won’t be disturbed. The key to concentration and meditation is to start with a short amount of time, say sixty seconds, to be successful with controlling your thoughts. Then add an extra thirty seconds to the time. Once successful with controlling your thoughts for ninety seconds, then add another thirty seconds. Follow this pattern until you can meditate for four minutes. Then just add minutes to the time instead of half-minutes.