How to improve focus and concentration...?

Everyone needs focus in life, it gives better productivity, less mistakes and greater satisfaction. To get focus everyone should (as I do) work behind the mind, that drives the mind.
It is “silence.” It is silence of the mind which gives focus. Mind engaged in several things at a time can’t produce focus. To bring silence of mind one can do the following things:

• Watching between thoughts.
• Watching from where a thought arises and where it ends.
• Watching the gap between in-breath and out-breath.
• And,
• Watching the watcher who is watching everything.

Final thought
Just work on silence of the mind, focus and concentration will come itself, it is the key of focus and of manifestation as well.