Art Of Manliness with 11 exercises that you can use to train your powers of concentration:

Research has shown that individuals who can sustain their attention for long periods of time perform better on all sorts of cognitive challenges than those who cannot. A man with a scatter-shot attention span will only be able to experience one plane of existence; he can skim across the surface of the world’s vast knowledge and wisdom, but is unable to dive deeper and discover the treasures below. The man with an iron-clad focus can do both; he is the boat captain and the pearl diver and the world is truly his oyster.

If you have a goal to learn and understand as much about the world as you possibly can before you die, strengthening your power of concentration is not an option, it’s a necessity.

A great article from Lifehacker on how to improve our attention spans in an overstimulated world. It focuses particularly on technology and working as a writer, but the same principles can be applied to any area where a boost of focus would be useful.

To get a longer attention span — even a span long enough to read this article — don’t worry about managing the information. Worry about managing your attention. Paying attention, for long periods of time, is a form of endurance athleticism. Like running a marathon, it requires practice and training to get the most out of it. It is as much Twitter’s fault that you have a short attention span as it is your closet’s fault it doesn’t have any running shoes in it. If you want the ability to focus on things for a long period of time, you need attention fitness.