There is a direct correlation between high performance and the ability to concentrate.
Predictions of future performance in athletes can be made based on their concentration skills.
A heightened ability to concentrate indicates future high levels of performance.
Concentration is a skill which must be learned, particularly since we live in highly distracting environments.
The continuous intrusion of information and our high degree of connectivity means there is always something else for our minds to latch on to other than the task at hand.
Think of your mind as a sniffer dog, trained to pick out and stay with one scent on the path among the hundreds of other scents it encounters.
But without proper training, a sniffer dog would follow any distracting scent it fancies.
Instead of finding the target, it would be off chasing rabbits through the forest.
The mental skill we need to learn is to recognise when our mind is off chasing rabbits and how to bring it back.
It is not a problem that your mind smells the rabbits and is tempted to follow them.
That is natural.
But a well-trained mind will note the distraction, resist the urge to go chasing after it and remain tracking the scent which leads to the desired result.
As with any skill, mastering concentration takes repeated practice.
Just as developing a muscle requires frequent, focused use of that muscle, the mind also needs to be taken to the "gym" for a focussed workout.
This is how to train your mind to stay focused:

1. Find a place where you can be comfortable and undisturbed for 5 - 10 minutes.
   
2. Sit comfortably with your feet flat on the floor, legs uncrossed and hands resting gently on your lap.
   
3. Close your eyes.
   
4. Focus on your breathing, the flow of the breath through you nostrils to your lungs
5. Count your breaths, counting one on the in breath, two on the outbreath and so on until you get to ten.
   Then start at one again.
   
6. Keep your mind on counting your breaths.
   
7. When another thought enters your mind, be aware of it but don't latch on to it.
   Let it go and keep your focus on your breathing.
   If you realise you have followed a thought for a while, let it go and return to your breathing.
   
8. Do this for five minutes (set a timer at the start if that helps you) and in future sessions increase it to 10 minutes or longer when it feels comfortable to do so.
   

The object of the exercise is not to stop thinking.
It is to become aware of your thoughts and strengthen your ability to stay with the object you have chosen to focus on (in this case your breathing).
Through this exercise you will develop awareness of how easily you run after your thoughts, how they control you rather than you controlling them.
Through practice, however, you will become better at recognising when your thought have run off, and you will improve your ability to return your thoughts to the object of your focus.
Don't become despondent when your mind wanders during the exercise.
This is not a challenge to see how long you can last without your mind wandering.
When your mind wanders (as it will) catch it in the act and then return your focus to your breathing.
Think of the wandering of your mind as you would the weight on the barbell in the gym.
The weight is the resistance against which the muscle has to work in order to develop.
The wandering mind is the resistance against which your focus has to work in order to develop.
Muscles develop to the point that the initial resistance (the weight) is easily overcome.
The same with your mind.
By adding more time to the exercise you increase the "weight" of the resistance your mind has to overcome, and the more resistance you overcome, the greater your powers of focused concentration become.