tu add content to clubs: images, videos, artículos etc. You're also active in general there, answering preguntas and commenting on things. The más people who fan your stuff, and the más comentarios your stuff gets, the faster tu ought to get a medal.
The system is a bit misceláneo though: some people get medallas for a small amount of stuff, while others take longer. People sometimes get medallas in clubes where they've been less active than the clubes where they've contributed more.
It takes a while, so tu really have to be patient. It took me about a año of being active here to get my first medal. It's better to just contribute for the sake of contributing, and just let the medallas happen.