Throughout life, everyone you interact with becomes your teacher. You learn something from all of them, whether it is positive or negative. It is vital to recognize the difference, and follow the positive!
In his book, Outliers, Malcolm Gladwell states the 10,000 Hour Rule. Whether it's physics or playing the violin, shooting baskets or writing well, the most important factor in mastering a complex subject is PRACTICE. Talent or innate ability gives you a small advantage, but it's not the most important factor. 10,000 hours works out to about 40 hours a week for five years. There are few exceptions to this rule.