"Pitching" is another word for "Querying," i.e. writing to an editor with a story idea you can execute. It doesn't take much to learn how to pitch. It takes a story idea that you've been chewing on for at least a few days, looking at all sides of it and testing your hypothesis.
In fact, most pitches require a little research to make sure your idea is sound or that your premise works. Once you find out that it does, you can make your argument strongly and without worrying that your editor will shoot holes in your pitch.
Queries should never be more than one page and e-mailed queries should be about two paragraphs. Many editors never read past the preview window, so you have to be concise. I'll chat more about queries tomorrow.