You should know what you want to get out of it. If the download numbers are not huge at the start, and most likely they won't be, then you need a reason to keep you motivated. A podcast could be a great idea for growing your business, or to meet new people. Commit to a set number of episodes and don't quit.

Prepare in advance, and make sure that you allocate plenty of time to work on the podcast. Not only will you actually enjoy the process if you give it enough time, but your show will be better for it.