Making a sandcastle is like an ideal version of how architecture should be - you can make mistakes, erase them and start again.

You need wet sand for the perfect construction. Build your castle as soon as possible after the tide has gone out. Dry sand is the enemy of the sandcastle builder.

To create my sandcastle, first draw a big circle in the sand (about 3m across). Then build your moat: dig down 30cm around your circle using a small metal spade rather than a plastic one, because these generally bend and break too easily.

Pile up the sand around the outside and inside as you are digging, and pat it down to form firm outside and inside walls for the moat, about 40cm high. Slope them slightly backwards so the walls don't collapse.

Next, draw a smaller circle inside your main circle, measuring roughly 1m across. Start building your castle by piling up and moulding the sand into a cone shape about 1.5m high. If you want, you could now start constructing walls between the castle and the moat which can be like little rooms to sit in. These can be as high or low as you want, depending on how big the person is who wants to sit there. A good tip for decoration is to get really wet sand (like the sand from under the water in your moat) and drip this down the sides of your castle; not only will it help hold the sandcastle together as it dries, but also give it a Gothic, Gaudi-esque feel.

Send helpers out to collect shells, pebbles, etc - you can make a series of arches on your castle and put stones all along the top of the walls for a nicely detailed surface. If you're really daring, you can make windows for the outer moat wall by carefully digging through. But be warned: it's risky and the wall could collapse, though that's part of the excitement.

Interview by Danielle Hine