I started learning the language in school (5th to 10th grade). I had a teacher who insisted very much on grammar which sucked while being a student, but in hindsight it turned out to be a good foundation.
With upcoming internet English became more and more a part of every day life, as there is more content in English availiabe than in my native language. In order to build up a proper vocabulary and to understand figures of speech and play on words I started to watch cartoons in English - first easy-to-understand-ones, like The Simpsons, because I knew the plot of the episodes already since they were aired dubbed on television. In the beginning I found South Park very hard to understand because they speak rather fast, but meanwhile I understand everything now.
Today I am able to speak fluenty.