Start with an ordinary object
Choose an object: a notebook, cup or lamp. Write its usual purpose, then five alternative uses. Gather possibilities before judging them. This is a creative exercise, not a psychological test.
Add a useful constraint
Choose one idea and add a constraint: it must help a student, work without electricity or use available materials. How does it change when the audience or constraint changes?
Turn the idea into a question
Sketch a first version in one minute. Ask someone what they understand without immediately explaining it. Record the gap between your intention and their interpretation, then choose one revision.