Commissioning agents at TV stations receive many proposals for shows. Yours must stand out from the rest. A good idea can often be a simple one. You only have a short time to impress. Remember, if it goes through there will be a pilot, and if that doesn't work the show will not continue. So you need to demonstrate your show is likely to run. Know your target audience and the sort of shows programmed by this particular TV company. Choose one that fits your style of writing.
Think of a good title for your idea. Remember, this is the first thing read, and if it doesn't catch their attention, that will be it. A show called "How I Met your Mother" possibly doesn't sound that promising but has proved successful. "How Clean Is Your House?" Would anyone care? They certainly did. So put forward any idea that you think is possible as you never know. Sometimes an obvious one works, such as "Lost" or "Glee." A play on words can be different and eye-catching, but everyone has a different sense of humor. However, if you can't think of a title, just leave the synopsis to do the work.
Write a short synopsis of the TV show using what, why, when, who, where and how. Name the characters, the setting, the main storyline and the style of the show. Keep this brief but imaginative as it will be either the first or second thing read. This is where the reader decides whether to continue or bin it, so it is important that it is engaging.
Work on "The Treatment." This is where you include all the characters, props, different scene set-ups (preferably not too many because of cost) clothes worn by the actors and possible budget. Keep this as low as possible. Money is clearly the main factor, and your show needs to be drawing in the viewers to get the most advertising revenue. Then you can increase the working budget for more elaborate scenes.
Write the first scene to give the TV commissioner a flavor of the characterization and verbal style. Let him see how you write. Bear in mind that the first person to read it will probably not be the decision-maker. If you know anyone in the industry, use those contacts.
Persistence pays. Don't be put off by rejection; try another TV company and keep writing. It is good practice, and you never know, you might be writing the next big million dollar show.