Mostly all the same steps you would take in developing a series or feature, just there’s a much more flexible “how long is this going to be” point.
- Determine world. Most miniseries take place in somewhat exaggerated or extreme worlds or settings.
- Determine character. The character is generally the center point, much more than a specific plot.
- Determine length. Is this going to be 3 hours? 6 hours? 10 hours? 12 hours? Are you breaking it up into hours? into half hours? into 90 minutes? This determines the structure of each individual episode.
- OUTLINE LIKE HELL! Do all the outlining. All of it. For the entire project. As if you were writing a script.
- Write the first episode. Look at your outline. Does it still match? If not, either rewrite the episode or COMPLETELY REDO the outline.
Hope this helps? I feel it’s rather generic of a response.