Here's an assignment with two clients, a broad subject matter and several rounds of sketches. Just thought you might be interested because it offers an unusual view into the illustration process by showing a variety of approaches to one, wide-open subject.
Trip Advisor and American Express teamed up and needed an illustration for a decal that would appear in restaurant windows. The drawing needed to convey "restaurant", "bistro", "cool neighborhood spot", "travel", maybe with people, maybe not. Indoors or outdoors, lunch or dinner, not breakfast, maybe a place setting. The Trip Advisor palette of bright green, sunny yellow and a tomato red would be featured. Many sketches were made, and here are some that made it to the final round, as well as the final piece (travel, outdoors, place setting, food, no people).
Important caveat: Although there was an unusually long sketch and development stage to this project, it was very enjoyable and the art director and client were easy to work with and very appreciative!