I have often described my process for writing software by paraphrasing the C programming strategy, "first make it work, then make it right, and, finally, make it fast" [Johnson and Kernighan, Byte 1983] .

"First make it work"

Use rapid prototyping to prove concepts, communicate with customers, and flesh out requirements.

"Then make it right"

Design and implement according to a growing set of requirements using iterative prototyping.

"Finally, make it fast"

Premature optimization must be avoided; fulfillment of performance requirements can only be judged after all of the other requirements are satisfied.