Any creative, whether a designer, entrepreneur, thought leader or other, can tell you creativity works best when the mind is at rest. You let your mind relax and wander and it starts connecting the dots in new and valuable ways.
This is now backed by new research, where "Neuroscience is finding that when we are idle, in leisure, our brains are most active."
Do nothing--sit anywhere, on the beach, by the pool, on a rock, and let your mind wander. Being bored with nothing to do is a boon for creativity. Draw what you see--when you're at a cafe or a restaurant waiting for your order to arrive, draw what you see. Imagine you're a child and don't worry about the quality of your drawing. Like with the photo exercise, it will help you remember the moment and notice details you wouldn't otherwise see. Play this game with your fellow travelers--fold a paper a couple times until its business card size. Draw something on it. Open it once and give it to the next person. They need to continue your drawing and then give it to the next person. Take the road less traveled--imagine you live here. Pick an address on Google Maps that interest you and go there. Once you arrive discover cafes, bookstores, local shops. Change your hours--if you're usually a late bird, wake up really early to watch the sunrise or to be the first person in the sea. If you're an early bird, stay up late and discover night life. In either case, take a siesta to pack on sleep. Learn something new--snorkeling, scuba diving, rock climbing, windsurfing, pottery, cooking, live drawing. Learning new skills helps you practice having a beginner's mind, a key state for creativity. Make a collage--collect bottle caps, sea shells, local food packaging, your boarding passes to make a collage in your sketchbook at breakfast or over drinks. Bring or buy a glue stick. Make unusual sand castles on the beach--try abstract forms like a cube, a cone or a pyramid.
Written on vacation, I myself am putting these exercises to practice.