Discover: Understand the needs and goals of the users. Document those needs and goals as user requirements.

Define: Quickly generate a prototype. Test it, test it, TEST IT!

Design: Based on user feedback, refine your requirements, and refine the design of the prototype. Test it again. Refine. Test. Refine. Test. (see a pattern?)

Develop: Use the final prototype as the first step toward the development of the finished product. Keep testing, never lose track of the needs and goals of the user.

Deliver: Hand it over. Grin. Wipe the sweat from your brow.