Instructions
Decide on the type of clan you'd like to form. Will it be a small group of just your friends, or do you intend to form a group of pro gamers? Choose a focus for your clan; some clans play one game, while others play many different games together.
Choose a clan name. If you have a core group of members, you can take suggestions from the group and vote on the best one. Do some research and choose a name with unique initials, since clans often display them on their gamertags to identify themselves.
Set up membership rules and procedures. After forming the core group, clans will often have an "audition" period for new members, while others allow open membership. Decide on behavioral guidelines, especially bannable offenses, and stick to them.
Create a clan website. Common features include a news feed, a calendar of events and forums for members to interact. Make it aesthetically pleasing, and update often; a well-designed site can serve as a good recruiting tool.