Improvisation: The act of making or doing something with whatever is available at the time.
Fate: The course of someone's life for someone or something, seen as outside their control.
Destiny: It is the force which some people believe controls the things that happen to you in your life.
Hence, there is a thin line between Fate and Destiny. One can improvise destiny but not fate!
Fate is, "being born into a noble family”, but destiny would be “Making oneself prosperous by working hard.”
Thus, Fate can’t be improvised while Destiny can be.
One can help others, gain good karma. In Christianity, doing things in the world for others is called “being a savior that suffers for the world". If you do good to others, others will also be good for you. Thus, more the wishes and blessings to us, and more chances of a long healthy and prosperous life, which we will owe to our destiny only.
Not only this, destiny is not all pervasive. Making good friends who are there for us in all circumstances, will make us feel blessed; thereby, helping us feel happy and satisfied in our life, and we will again owe destiny responsible for it. These two illustrations, simply suggest that it is in our hands to lead a life that is satisfactory and praise our destiny for it then.