As with most things in life, sometimes a simple approach really is the best. I found “Lean UX” a helpful and comprehensive book which provided a clear departure from the old fashioned product development cycle.
In Lean UX, Jeff and Josh stress the importance of collaborative design – getting the whole team AND clients involved as early in the process as possible. Cross-functional teams are formed which continuously validate assumptions while, developing and re-developing products in an Agile environment and of course learn from their mistakes and assumptions throughout the process.
Not only would I recommend this to a friend, I’d recommend it to the entire team!