Get rocks, throw on garden, plant up.

Really need a bit more info...size of area, aspect, what rocks do you have or intend to use, soil type, what do you want to grow etc etc

Try to echo a natural landscape. Fewer, bigger rocks far better than lots of little rocks. Get strata lines in the rocks lined up as if naturally fallen together. Sloped back slightly to catch water and, with fissures between to plant into. It goes on, great fun to do, with a very rewarding result if carefully done. I've built several, in all types of rock, with taken to choose the correct plants for the rock type. Moongrower and Bulbaholic may well have more to add.

Im the head gardener for the largest municiple rock garden in Euroope so know a bit about what im talking about https://www.facebook.com/PrestonRockGarden Although im sure bulbaholic and moongrower can give you better advice

I believe we all have something to contribute Andyj.
Rockeries cover a wide range of ideas and not all go to the trouble to do it the way Worthy suggests and sadly some can look horrendous, but most mature to look great.
Why not look on Goypeadia Rockery ideas page there are 209 photos of what members have done, which may give you some ideas.

Andy, I know, not suggesting otherwise. I was tapping into their alpine soc. links to get 'em to join in. In a funny way your joke method can sometimes work, can't it? I've acquired several tons of waterworn limestone a few years ago. Bits of it used all over the place, but I've kept the best for me. Just haven't got a garden at the moment, only a garden centre. The fossils in the stone are lovely, and it's a bit mind-blowing to think it's a few hundred million years old.

I remember seeing fossils in limestone in Derbyshire when I was quite small and it blew my mind when Mum told me that they were sea shellfish - couldn't imagine a submerged Derbyshire!