There are 3 major clans in Amon Thranduil/Mirkwood and we do ask all citizens to join one of them. The clan you will join depends heavily upon the job you have want, but that is not the only factor that will determine it.
The Laiquendi or green elves are also known as the Singers of Ossiriand. Singers, artists, diplomats, minstrels and historians would belong to this clan.
The Laiquendi common room is inside the halls of Amon Thranduil.
The Erynedhrim or the wood elves of Mirkwood are another clan. Warriors, smiths, guards, hunters and scouts would belong to this clan.
The Erynedhrim common quarters are up in the Beeches just west of the halls.
The Duinedhrim or the river elves of Mirkwood are the third clan. Traders, brewers, clothiers, jewellers and innkeepers would belong to this clan. The Duinedhrim clan house is in Celebannon, where most of the Duinedhrim live.

Before they began the journey to the West, the elves divided themselves up into three clans, the Vanyar, the Noldor, and the Teleri. When Orome came to lead the elves to Valinor, it was hotly debated among the elves whether or not to accept these summons. The Noldor and Vanyar undertook the march, but some of the Teleri chose to stay behind in the far east. These became the Avari, or Dark Elves.
Along the march, some of the Teleri changed their minds. They stayed in Greenwood the Great, on the eastern side of the Misty Mountains, and became known as the Nandor, those who turn back. Because they chose a forest for their home, they also became known as the Silvan elves. It is this group who comprises most of the population of Amon Thranduil.
Silvan elves tend to be outdoorish types. The love nature, especially the forest. They have adopted the Sindarin language for most day-to-day speech, though they also speak Bethteur, an older form of the language. A very few among them even know Quenya, the language of the High Elves of the West, although its speech is banned from use in Thranduil's realm.
The Silvan elves tend to stay to their own realm more than other elves. Though they enjoy contact with the outside world, they would prefer to stay in their forest, fighting the evil that has taken root there. But for the most part they are a merry folk, singing and laughing and telling stories.
