The best way to become the best at something is to choose that "something" wisely. For example, Scott Adams, creator of one of the most successful cartoons:
> Recapping my skill set: I have poor art skills, mediocre business skills, good but not great writing talent, and an early knowledge of the Internet. And I have a good but not great sense of humor. I’m like one big mediocre soup. None of my skills are world-class, but when my mediocre skills are combined, they become a powerful market force.
More info here (and in Scott Adams' book): [1]
It's like Google AdWords: very difficult to rank highly for one keyword, but possible for a set of three or more related keywords.
Adams alludes to the fact you don't have to be the best to succeed; there are alternate roads to success. Another take on this is "relative expertise." You don't have to be the foremost expert on a subject before you can help others; you just need to know more than the person you're helping.
[1]: http://sourcesofinsight.com/scott-adams-success-formula/