When you write down your ideas you automatically focus your full attention on them. Few if any of us can write one thought and think another at the same time. Thus a pencil and paper make excellent concentration tools. Michael LeBoeuf
Lack of concentration is a major problem in all aspects of time management. A list of some of the things causing it might include:
The remedy for all of these is consistent use of a time-management list, whatever the method. The writing focuses your attention. The scanning provides a framework. And the selection directs your attention to one subject.
The more you practise this, the more effective it will be. Consistency is the keyword. Sporadic use or constantly jumping from one method to another will simply increase the amount of distraction you experience.