It is important to define the basic flow of a use case before building the structure of the several flows that are part of it. If the speed with which the use case is completed by the actor is important, then it must be optimised to be as efficient as possible for the user. This is especially true if the use case will be used by an actor under time pressure, for example, someone answering a customer call and expected to provide real-time answers to customer queries. Use the following as a guideline:

	Write the most important course of events or what happens most of the time
	Do not include complex exceptions in the flow text
	Simple exceptions with a simple condition and a one line response may be included. This is simpler than creating an alternate flow.
	Write a complete sequence of events with no large time gaps. Start with the system in a stable state and finish with it in a stable state.
	Write it in the Use Case Document
	Note alternate flows that need to be handled but don't spend time elaborating them at this point