The best advice I came across on the subject of Concentration.
Wherever you are and whatever you are doing, be there, be present.
When you work, work. When you play, play. Don’t mix the two.
Give whatever you are doing and whoever you are with the gift of attention. If you give the gift of attention, you will receive more attention in return and it feels really nice and appreciated for either.
On the way to work, concentrate on what you are doing - not the work.
Pay attention and give attention. Don’t just drift through the day with no direction and your thoughts going in all directions.
It takes some time to develop this habit...but once its built you feel more focused, sharp minded and confident!
Trust me, this can only be an "experience" to go by. You have to do it if you want to be that someone different and unique.
This is what I learnt from one of my favorite books, implemented over time and now sharing it with you because I have experienced it for myself and know the value of it.