In case none of you saw, expert architect, Renzo Piano, was mentioned in a Yahoo News article about the best advice he could give for building sandcastles. Just to a Google search on this guy and his wikipedia page is loaded with famous buildings that he's designed, like the famous Shard tower in London.
Basically, his advice in a pictogram here, is to keep it simple:
1. Find a spot near the water, but not at the water's immediate edge.
2. Eyeball an 18" diameter circle on the sand and dig out a mote that is a foot deep around the diameter.
3. Include a channel to the mote that connects to the water's edge.
4. Build up about 2 feet of sand on the diameter.
5. Form your sandcastle from this chunk of sand, carving as you go.
6. Stick a paper flag (or a cocktail umbrella) onto the top of the highest point so everyone knows that it's a castle and not just a lump of sand.
Pretty simple stuff, right? And for everyone trotting to the beach this summer, click here for info on how to make a perfect beach tote!