Read an article on Wiki about sand castles that lead me to “World Grandmaster Sand Sculpting Champion Rich Varano” and his web site.
He’s from Florida, so I’m sure he has a lot more access to sand to practice and ply his trade than most people. Evidently he travels all over the world to compete in sand castle building competitions. The photos on his website are awe inspiring. Check it out for inspiration before you head to the beach this summer. If you need lessons, he gives them!