It takes fine sand to be able to make the detail on his face, and a spray bottle of fresh water to occasionally re-wet it. Of course, the larger you make the character, the easier the detail is to make. But when it is just me and a shovel, about 3 or 4 ft tall is as big as I can make it!
Done with the head!
Notice the difference between the first photo and this one. The first photo is in the full sun, this one is taken under the shade of an umbrella.