Technical excellence as well as good design doesn't matter, the most important is to deliver as fast as possible.

Business people and developers must communicate only when needed, preferably via email.

Working software is the primary measure of progress.

Deliver working software frequently, from a couple of weeks to a couple of months, with a preference to the shorter timescale.

Welcome changing requirements, even late in development. Agile processes harness change for the customer's competitive advantage.