I'd have to say, the heart of a clan is an active and loyal member base. Loyalty is a must, but once the activity dies down, suitable replacements must be found in order to inject that activity. Evil as a clan has been democratic in terms of electing new leaders/etc which has been one of the reasons for our extended span of existence in comparison to most clans, along with a core of members who have remained and passed down their knowledge through the eras of toribash. Looking at clans Urban and Evolution, I can tell you that a clan's success isn't limited to the variables I listed previously, Evolution has always maintained a very competitive level and has yet to drop below its competitors. Urban has always clung to life and has at times been one of the best clans out there. To look at what makes successful clans, you have to take a gander at the dead clans too, as they are examples of what has failed. The most important part of any clan is sustainability, if the clan is absolutely amazing for a couple months and then it dies, it isn't a good clan as far as i'm concerned.