I head up a quilting community each month. Sort of like a combination Bee & guild. We all bring projects to work on. But, we always try to have 2 demos. We take turns doing it. We keep the demos short - usually around 15 minutes. We show either a block or technique. The person doing the demo usually has several steps already done. So, they can say this is the way to cut it, then sew this seam. Here I already have all the seams sewn, then you do this... So, even if the block is pretty complicated, by having several demos steps already done, it can be done quickly. By us taking turns doing the demos, no one has too much work to do, or wastes too much fabric for a demo. And we learn alot! By teaching we have to first learn it ourselves. Alot of times the block or technique that we volunteer to demo, is because it is on our personal bucket lists.