Contribute. Lots. I have one medal, from the Bleach ऐनीमे club and I got that from monthes of endless contribution to pop क्विज़ questions, the forums, adding pictures, commenting and making प्रशंसक picks.
Also, be aware of how आप treat others, because that also comes into it. If आप are a well-liked user, then it'll make it slightly easier. XD