How do I pitch an idea for a TV show if I don't know anyone in the industry?

First, and foremost, whatever you write, get it copyrighted, (once in the industry, you will quickly find out why). You can do this simply by having the idea published in any magazine or newspaper. Even putting a personal ad in the newspaper describing the idea in some detail would be sufficient to secure future rights to the idea. Talk to a property lawyer, he will provide you with everything you need to proceed securely. And you do know people in the industry - their names are on every show that they produce, and they have offices - if it is a good enough idea, they will either pass it off to someone they know who can handle it, or attempt to handle it themselves. Also, you can probably find a recent copy of Variety magazine in the main branch of your city's library, or find it on the web.