Bookmark the casting sites for every network airing a reality show. Check the sites frequently for casting updates, which will explain the who, where and when for all auditions, as well as how to submit audition tapes.
Keep up with industry-related sites like realitywanted.com. That website lists casting calls and audition offers for reality and game shows. As of 2011, it also had links to social networks connected to the shows, and interviews with producers about why and how they cast their shows.
Apply to as many shows as possible. There is no limit to how many times you can apply, so you have nothing to lose.
Be larger than life in any audition tape or interview. While the shows tend to cast opposite types, they are more likely to latch on to someone "memorable" whose personality will translate well on television. If you are quiet, shy or reserved, a reality show is probably not for you.
Be yourself, but yourself turned up a few notches. The producers are used to working with actors. If you attempt to be a "character" just to get on the show, they will see through you. If you do make it past an audition, you could be faced with having to stay in that character throughout the show. That's fine for pro wrestling, but may not work well in a reality show setting.