The ability to concentrate makes a person very powerful.
Signs of real concentrating
If a person is concentrating on something properly, then all sorts of other things that they are not concentrating on can happen and they will not even notice. An could be reading a book and they do not even notice an explosion.
How to concentrate
The first thing is not to be selfish. Being selfish means a person is led astray by whatever things appear that they may want. This can make them excessively scared in scary situations, excessively excited in exciting situations that means they do not concentrate.
Emotions and feelings are essential, they are a person’s energy, what they use to feel on a psychological level etc.
However selfishness can make a person’s emotions and feelings so unbalanced in certain directions, that it will be impossible to concentrate. For example if someone is excessively excited about a reward or scarred of loosing something.