Basically, da being an active member of a club and contributing things which others like: 1. Getting the links, articles, immagini and video you've added fanned 2. Answering lots of questions, sondaggi etc. 3. It's easier to get medaglie in più active club than dormant ones.
I don't think there's a set number of fan o contributions. The system's pretty random. Sometimes it doesn't really make sense.