tThere are many methods to increase your concentration. My favorite is line drawing. I learned this technique in high school, and have used it throughout my art career. What is involved? Place a pen or pencil on a blank piece of paper. Focus on the object you want to draw. Leave the pencil or pen on the paper, not removing it while you study your subject/object. Do not allow your attention to waver. Do not look down at the paper. Do not remove the pen/pencil.
At first, the result may not be pleasing. As you practice, it does improve. John Lennon and Diego Rivera used this technique! My work has won awards using it. You can see pieces here, or visit www.artistbe.com under my name. Artistbe offers reproductions at reasonable rates.
So, how does this improve concentration? While you are doing this exercise, you have to be totally aware. You cannot let your mind wander. You have to be relaxed and fully in the moment. Being fully in the moment is what many gurus are recommending for a more fulfilling, alive existence. You can learn to do that with meditation; that is not something many people find time to do. You can achieve this state through dancing or being involved in creating music, or some craft, or some other activity that requires your full attention. This is just one of many ways to achieve a sharpness of mind. It is one of my personal favorites. Try it and see how it works for you!