Pick a topic you really like or that you understand well. Then, check to see if there are other podcasts about the same topic. Remember: if there are a lot of podcasts about the same theme, it’ll be more difficult to reach listeners. So, it’s very important that your podcast be original. Finally, you must give your podcast a name. Choose one that suggests what it is about.
It’s the type of podcast: solo (or with co-hosts), interview, storytelling, group discussion, etc. Think about how the content will be arranged: Will there be a general segment (a podcast about entertainment, for example) or a specific segment (a podcast about movies, for example)? Will there be music? Will there be an explanatory introduction? Will there be more than one topic per show?
It depends on the content. Can you explore everything in 5 minutes, 15 minutes, or will it take about an hour? Try to be consistent in respecting the length for each episode. It is important for two reasons: 1. it lets listeners know how much time they will have to invest; 2. it helps you decide how much content you want to include in each episode.
How often should you launch a new episode? Consider how long it takes to produce an episode (a 15-minute podcast will take at least 2 hours to research, script, record, edit and post) and then decide on its frequency. Once you make up your mind, stick to it. When you have followers, your podcast becomes part of their routine.