I look for groups in The Classifieds Forum. If you find a clan of people that are looking for recruits, try sending their leader a message over Bungie.net saying you would like to face them. Make sure you find a pretty successful clan- every time that there is a clan with about 5-15 people, they end up declining... Also make sure that they are devoted to doing regular clan activities. Dont challenge a picture taking group to playing a clan battle because they probably do not do anything related to competitive gaming.... If that doesnt work, use Gamebattles....