How can the three-step process be adapted to podcasting?

The three-step writing process adapts quite nicely to podcasting.
First, focus the planning step on analyzing the situation, gathering the information you’ll need, and organizing your material. One vital planning step depends on whether you intend to create podcasts for limited use and distribution or to create a podcasting channel with regular recordings on a consistent theme, designed for a wider public audience. As with planning a blog, if you intend to create a podcasting channel, be sure to think through the range of topics you want to address over time to verify that you have a sustainable purpose. If you bounce from one theme to another, you risk losing your audience.
As you organize the content for a podcast, pay close attention to previews, transitions, and reviews to make sure your audience successfully receives and interprets your message on the first try. Unless you need to capture exact wording, speak from an outline and notes rather than a prepared script. However, don’t try to make up your content on the fly.
Effective podcasts, like effective stories, have a clear beginning, middle, and end.
The completing step is where podcasting differs most dramatically from written communication, for the obvious reason that you are recording and distributing audio or video files. Particularly for more formal podcasts, start by revising your script or thinking through your speaking notes before you begin to record. The closer you can get to recording your podcasts in one take, the more productive you’ll be.