When you're in a clan, you'll find a number of helpful perks. You can compete against other members of the clan, or share strategies and techniques. It's also possible to donate cards you don't need, to help other players. They might well return the favor. If you're stuck on something, it's also easy to get advice from your fellow clan members. If you can't find a clan to join, you can always create one of your own, but that will cost precious Gold. You're better of joining someone else's group, if possible, and earning cards and experience at an accelerated rate right from the start.