My ustazah had informed me that we need to believe in everything of what ALLAH had destined to us. Her father had said that even a single piece of a leaf will have the permission of ALLAH to drop. So, all incidents that happened to us are all destined. No such thing as coincidence. Why? Ask your faith. How you perceive your destiny is how you practice your way of life. If you do not do anything to alter your destiny, you will remain just as before. This is because we have to be smart enough to strive for success. ALLAH wants His slaves to think and make efforts in order to succeed in all aspects of life. We need to compete and at the same time try not to forget our life "over there". If we try to attain success just for the world, you will lose you life over there.
Many of us think that everything is destined in this life. Yes you are right in term that something you have the choice to choose whether you want to do it or not. Let me give you an example, you are hungry and ALLAH had given you the money to buy something. So, you now have the choice to eat rice or fried noodles. By the way, you also have the chance to eat something that is not halal. For example, pork and something that you do not know the status of halal. I think this is clearly defined how you can choose your destiny in life and how you can make sure you will get the best in life. Allah had destined the destiny but you will have the ability and power to choose. Choose the best in order to sustain success in your life as a Muslim.