The idea of pitching used to terrify me. (And to be fair, I haven't had an official pitch meeting with producers or executives yet.) But I'm always informally pitching my ideas to people - and I think it's a crucial skill for working out your ideas, and seeing how other people respond to them.
If you tell someone about an idea and can't boil it down to a sentence or two, that's a problem. You need a simple logline like "A woman has to make it to Canada in time to save her husband from terrorists who ride elk." If you can't simplify the story, you might have too many elements, or it might be unfocused. The protagonist, theme, conflict and character arc/journey should be clear in your head, enabling you to communicate these things to others.
Comparing your idea to other movies or shows often helps people understand the tone of your piece. A workplace comedy like OFFICE SPACE is a lot different from a romantic comedy like IT'S COMPLICATED. Just make sure you're using movies and shows that were successful. Nobody wants to hear a pitch for a movie that's THE HOTTIE AND THE NOTTIE meets CAVEMEN.
Remember that people always respond to passion. Why did you choose to write this idea? What is so interesting about it? If you're able to make other people see why it's so compelling, you're halfway there. Pitch your idea to lots of people as you develop it. They might recommend similar TV shows or movies you haven't seen, or give you a new perspective to perfect or even re-imagine your idea.
Unless you're asking a close friend to help you with a writing dilemma, don't get into all the things that are wrong with your idea. Don't poison the pitch (or read). See what people respond to and have trouble with on their own. The writing landscape is already really competitive, so don't give people a reason to dismiss you. Be your own biggest advocate.