Someone once said to me that if you try your hardest you could do everything 

My teacher said to me that if i imagined something that i really want and try to achieve it i would get it 

My parent always says to me that if you make the best the result  will be the best 

But why even i 've try my hardest, even i've try to imagined it ,even i try my best  

It will never come to real

i will never get to hold it .

could you tell me why? Am i doing it in a wrong way?