The step you skipped is one you learned long ago. It stopped feeling like a step and now it is just true, so your brain fills the gap and tells you nothing. It is like a recipe that says "make the sauce" and stops there. The cook knows what that means, but a new cook has no clue.
One study gave this a name, the curse of knowledge. People who knew more were worse at guessing what a new person could follow. So going over your class again will not find the hole, because you are the one who can't see it.
Ask a person who does not know the thing yet. Write the steps as a list with numbers and hand it to a person who has never done it. Then say nothing while they try. The spot where they stop is the step you skipped.
## A worked example
Say you teach people to price a workshop, and step three says "set your rate" with no more words. You have done it a hundred times, so it feels like one step. Your friend from a new job asks "rate of what, per hour or per person?" and you see it was three steps. A person who knew the answer would never ask. So you add plain words, like "pick what one person pays for the whole workshop," and you try it on a new person. Your first friend now knows what you meant, so a new person is the only fair test.
Use one person and not a group. A group fills in the gaps for each other. One person is like a new cook alone with your recipe, so the missing sauce step shows up fast.
Watch out for the polite nod. Most people say yes when you ask if it makes sense. Ask them to say the last step back in their own words.
The sheet has the tell words that mark a skipped step, a test for a beginner, and the research on why you can't see it.
Where this comes from: Camerer, Loewenstein and Weber, 1989, Journal of Political Economy.