Perfection is the perfect excuse for procrastination. Most people start with a bang, but quickly fizzle out. The iTunes library is filled with people that had good intentions, but burned out after just a few podcasts.
1) Give tips, news and advice of value.
2) Be passionate and expert in your topic.
3) Outline what you want to talk about.
4) Be consistent in your program's format.
5) Make the production process repeatable.
6) Stay on topic to meet audience expectations.
7) Have your take and don't suck. Practice first.
8) Most importantly... don't be perfect.
Don't worry about small imperfections in speech, or little blunders. Or if you're video podcasting, don't worry about your hair. (Be mindful of background distractions though.)
Practice yourself talking into a microphone, or on camera. It's how the rest of the world sees you 365 days a year. So get used to it, and get over it. Just get busy making your podcast.
For video, use the camera in the lid of your laptop. It's good enough. For audio, pick up a 100 dollar Samson CO1U USB condenser mic, and just go for it. Get Apple's 35 dollar QuickTime Pro (Mac or PC). Use it to encode your audio in AAC and video with the H.264 codec. This is all the gear you'll need to get started.
You'll reach a much wider audience, and pick up more new subscribers, than you could have, by advertising, or any other method. You can get listed in YouTube, iTunes, RSS, and podcast news feeds. Your show be available to over 50 million people that listen to podcasts.
Remember, it's early in the game. There are no clear leaders in audio podcasting. Even fewer still in video. It doesn't matter if you podcast news, opinion, humor, tech talk, politics or how-to shows. Now is your chance, to position yourself as thought leader, and brand yourself as first, in any category you choose.
So be passionate. Be knowledgeable. Be exceptional. Be remarkable. But don't be perfect. Just be yourself and let your personality shine through.