I’ve just come back from running a workshop at Webstock in New Zealand, followed by another one in Hong Kong. I heartily concur with Tim’s advice here. I’ve certainly migrated to having a more modular approach to workshops. In fact, these days I have little to no slides. Instead, it’s all about being flexible.
You can spend forever carefully crafting and refining your workshop and coming up with solid exercises but at the end of the day, you need to be ready to go with the flow.
Some sections you wanted to cover you may not get to. Some topics you hadn’t allotted a lot of time to may need to become more detailed. That’s all fine because the workshop is about helping them, not yourself.