I am a liberal Hindu with a missionary-led convent education so you will get a mix of both beliefs with my own thrown in for good measure.
I think Destiny (what is pre-ordained) and your Deeds are two important wheels of your cart. They both get you going ahead and if one or both the wheels are not working well then you are bound to slow down or stop.
While Destiny gives you the canvas, your deeds are the tools with which you paint that magnificent art piece on your lifescape.
On the dismal note, there have been cases of people who gave their best but didn't get back their due or there were those who got famous only posthumously. There are some among us who may not be as intelligent or diligent or industrious yet they seem to be making a killing and then there are some others who have all the qualities but may remain unsung and unrewarded.
On the sunny side, one needs to persevere and continue endeavouring to see what lies in store. If you donot get up and open the door, opportunity would knock and walk away. With incessant effort there is the satisfaction that YOU did your best AND that's more than half the battle won; for you are the master of what you can control, the rest is beyond you.
While Destiny is a formidable ally or adversary depending on YOUR roll of the dice, but it is best to be a KARMAYOGI (continue doing your deeds without worrying about the fruit - as the great scripture GITA propounds).
Be ready, sharp and shining when HE throws a SIX at you.