Writing Feedback / if you do not do this, you will not have a successful life? [5]

Hi everybody . I really really need people to read my essay and tell me how can i improve it .
Please HELP !

prompt:
Do you agree or disagree with the following statement? Some people think that making sure the influential people or potential employers know about your strength or accomplishments can help you succeed, if you do not do this, you will not have a successful life.

my essay:
It is not uncommon to see different people from all walks of life showing themselves in a variety of reality television shows such as 'American Idol', 'Britain's Got Talent' and the like. But I fundamentally disagree with the speaker's claim. Being successful is far more than presenting your advantages to influential people or potential employers. Although it helps, it never determines.

Admittedly, letting influential people or potential employers know about your strengths and accomplishments does add more possibilities to your success because sometimes it means a precious opportunity. For instance, when you are applying for graduate school, a reference letter from a celebrated professor definitely allows you to stand out from the rest of the applicants. Before you get the letter, you have to show the professor your talent. Also, when you seek a promotion in your company, you have to prove to your boss that you are qualified for the position.

However, opportunity is not the most essential contributor to one's success in life. As we know, perseverance keeps bright the key that opens the treasure of achievement. If Hugh Miller, after toiling all day in quarry, had devoted his evenings to rest and recreation, he would never have been a famous geologist. The celebrated mathematician, Edmund Stone, would never have published a mathematical dictionary, never have found the key to science of mathematics if he had given his spare moments to idleness. Had the little Scotch lad, Ferguson, allowed the busy brain to go to sleep while he tended sheep on the hillside, instead of calculating the position of the stars by a string of beads, he would never have become a famous astronomer. Though these examples may sound too special at first glance, it actually represents many other people who had rest their success upon industry. Without diligence, even if influential people or potential employers have offered you an excellent chance, you may ruin it as well. In conclusion, I prefer to look at the way to success as a course mainly determined by internal causes, and in my opinion, perseverance and diligence are the crucial elements that help us to acquire success.

In a sentence, constancy makes success a certainty. We should remember a worthy proverb 'Constant dripping of water wears away a stone.'