Identify actors (roles outside the system: Customer, Member, Clerk, Manager) and what each needs to do.

Group related functionality into use cases (one user goal each), not one use case per button.

Initial diagram: actors linked to the use cases they start.

Refined diagram: generalize actors (Member is a Customer), factor shared steps with <<include>>, optional ones with <<extend>>.

Common errors: use cases that are steps rather than goals, the system shown as an actor, functional decomposition, missing actors.