In the book Outliers by Malcom Gladwell, he states the 10,000 hour rule; that is, to become successful in any enterprise, you have to practise for 10,000 hours.
He cites studies of violinists and divides the people who are capable of becoming world class musicians, and the people who are good enough to become music school teachers. The difference is in the number of hours one plays.
Please forget about talent for a moment. Talent, undoubtedly, plays a part, but after you average it out, it takes roughly 10,000 hours of practise to become really good at something. For example, a saleperson has to practise his sales pitch to clients many many times before he can deliver the pitch smoothly. However it takes more practise to learn the art of the close, as well as to recognize the customers body language and do the proper pitch.
The book also gave an example on a guy called Bill Joy (if I remember correctly) and Bill Gates. Both were forunate to have he change to practise their computer programming skills so much during their university and teenage years respectively that when it is their turn to step up and program, they are more than good enough. Which is why the first guy is the founder of sun microsystems, and the other, as everyone knows, Microsoft.
Even Steve Jobs had practise assembling and designing his own computers.
I once read a quote from Bruce Lee that goes like this: I do not fear the man who practises 10,000 kicks one time each, but one kick 10,000 times.
Practise indeed makes perfect. If anyone doubts the examples because they are written, then I shall provide my own example. I obtained good results in programming aspects of my modules in NUS for just one simple reason.
I started making my own websites when i was 13. I learnt HTML, then CSS. Both are not programming, but it led me to learn PHP, and by the time I took my own programming module, I had already built a tuition website with a database of tutors. Although I did not practise 10,000 hours, it gave me a great headstart. If I had spent 10,000 hours on it, I might have been much better.
A little bit of practise goes a long way. Hence work hard and practise your trade for 10,000 hours so you will be good at it.