Just as we advance science not just by positing new theories but also by doing experiments to verify them, reliable design success requires doing design research. Repeatedly and rapidly generating ideas — while deferring critical assessment — increases the quality and speed of creative ideation. Good design means running experiments — building prototypes and testing them with users who are representative of your target audience — so you can select the best ones and then refine them. Never treat a result as final — each increment corrects shortcomings in the previous iteration and creates additional customer value. Design is how things work, not just how they look; therefore, good design is based on both art- and science-rooted principles.