Write a few sample TV scripts. Traditionally, writers would write a sample script of an existing show. However, it's also acceptable to write a sample pilot of your own original show.
Submit your sample scripts to television agents or Writer's Guild of America TV writer training programs. Most writers seeking a story editor position already have an agent, whether they've actually worked on a show or not.
Get hired to be a staff writer on a TV show. Learn everything you can about the process. Attend the writer's room meetings regularly. Do quality work on scripts that you're assigned.
Lobby for a promotion. If you're fortunate to be asked back to the same show for a second season, try to get your credit bumped up from staff writer to story editor. If you want to look for work on a different show, have your agent seek a position as a story editor.
Read the industry trade magazines, communications journals or media industry classifieds for any new reality shows going into production. Alternate job titles for a story editor in reality TV includes reality TV writer or story producer.
Apply for a job as a reality TV story editor/writer/producer. Submit your resume and qualifications directly to the production company or through the job seeking service where you found the ad.
Work behind the scenes on the show, if hired. While reality TV shows pretend to be spontaneous, it's the story editor who essentially "writes" the events that happen during the show. You need to create scenarios for the characters.
You'll also be responsible for creating drama and conflict by putting clashing personalities in situations with each other. During post-production, along with the editor you'll need to help take raw footage and shape it into some sort of storyline.