My students come in prepared. They know the drill. But, workshops that aren't well organized often lose the interests of the artists they are trying to motivate. To run a workshop successfully, you have to be ready when the students come to your door. As it is known that you are Never to busy to learn art, hence to follow your passion, you need to plan your schedule accordingly.
Occasionally as artists, we get so used to doing artwork for ourselves that we forget how to teach it. I have sat in on some art workshops and watched the lesson just fall away because the artist, one of my former pupils, had forgotten how to express the art concept for the day's lesson. That should never happen.
You may not have a wonderful quantity of time on your hands. But if you're running an art workshop, you need to find the opportunity to review what concept you're going to be getting across for the day. You already know the material. However, it's at the back of your mind somewhere. All you've got to do is review the material and get it all back to the forefront of your mind.
It normally takes me about five minutes to discuss everything that I will be introducing to a specific class. Five minutes is not at all hard to discover. And yes, I still need to reassess my own material. There is nothing to be ashamed of doing.
However, introducing a notion only requires a couple of minutes anyway. After that, it is the hands-on experience. Other students may become involved in the learning procedure. You need to encourage that. It makes them excited.