"Be in the Present" or "Be in the Now"
We control the future by the present; and the present is molded by the past. We can't change the past. It has already happened. The future hasn't arrived yet. However, we can create a great future by making best use of the present.
Live in "The Present" i.e.; Live in "The Now"
This is most easily accomplished by attaining a higher state of consciousness where the small self has realized it's Universal nature. A person then is always naturally and effortlessly fully absorbed in the Self and lives every moment with the unlimited potential of natural law guiding him/her. There is only "Now" and at the same time, there is always Infinity, happiness, Bliss, creativity and Intelligence.
This is a great Life to live and it is well-worth striving for.
Have a great day.