Every artist -- writer, graphics, dancer, musician -- has a "process." TBH, I hate words like "process" and "organic" and "the universal concept of transposing my inner most process into an organic whole that transcends this that and the other thing."
Still there is a process that each of us uses to create something out of nothing. And no one process is better than another. Find yours and work with it until it all flows smoothly. But for me, here is how I came up with La Casa at
http://www.webmousepublications.com/uru-website/cleft-road/cleft-gate.html
The Question -- my first clue into what I wanted to do was based on what I wanted to know. What was on the other side of the fence around the Cleft? In the novel I recall that the Cleft's terrestrial whereabouts were not defined, but once URU placed it in New Mexico I wanted to know why the Cleft had remained undisturbed in all those centuries of humans tramping above.
An Answer -- got the question, now imagination fills in rest. New Mexico lies outside that fence and it has a set history, one that I can research and weave into the context of Cyan's story of URU. People lived all over the area for thousands of years before the coming of the D'ni and those surface dwellers are still there.
By taking the line that this is a surface story, rather than a strictly D'ni one, my writing team has the freedom to create characters and place them in the story without disturbing canon. More questions rose. I can explain why the local Navajo would not have tampered with the Cleft, but not the inquisitive, acquisitive Europeans. With help from Ms. Isis we created characters -- some white, some Navajo. Some have lived in the area for generations, long before John Loftin and Elias Zandi found the Cavern. The younger characters are those who heard Yeesha's call and arrived to explore below.
Outside the fence there are roads, towns, tribal villages and widely spaced hogans. Explorers come from somewhere, so perhaps they landed at airports in Gallup and Albuquerque. Maybe they took the bus, maybe they drove in cars. Our Spanish mission called La Casa was built around the time that the D'ni were destroyed. Anna was probably a European woman, very likely Spanish in origin. She and young Atrus remained at the Cleft while around them the Navajo battled encroaching Europeans.
Once I had the Navajo placed in the area a lot of answers came easily. Why was the Cleft left undisturbed over the years since Anna's death, Yeesha's departure and the discovery of the Cavern in the late 1980s? Navajo would never have gone near the place. One sight of bahro dancing on the mountain's rim would have kept them away -- let alone the rumors of mass death in the ground below.
Each question that rises deserves an answer. I find that "instancing" can hide a multitude of sins. Why does it only rain on that patch of the desert? Instancing. Why haven't modern scientists gone ga-ga over the fallen viewer and the exposed alien animal bones. Instancing. When you drink the vision tea in your bedroom at La Casa and wake up in a different room, why do you never catch the young lady stepping out of her shower right then? Instancing.
Working out the details of La Casa in an HTML based format is not unlike the first Myst world. It is single-player and totally static. My graphic skills are not great, but I am managing as best I can. What I have learned from this experience is getting the story elements out there in a non-linear manner. You will find some details in the radio interviews. Others are in the books in La Casa's library. There are things to learn by talking with the characters.
I would recommend that anyone who has a good age idea but is stumped by the overwhelming learning curve of mastering a 3D rendering program to take a stab at writing it out in HTML. The coding is not that hard -- and there are programs that will do all the coding for you. You can control what the reader finds and where the reader goes by the embedded links. For instance, at La Casa you can check into any room you like and if you want to try a visionary dream, you can call the front desk. Most of these dreams will return you to your own room, but some will cause you to wake up in a different room -- and it is in those rooms that we have hidden other books.
In time we hope we can link new age books in this way, including age books from other writers who just want a chance to show off what they have.
Someone once said "I could have been a great poet, but the seats in the library were too hard." Don't let that be you. Create and don't be embarrassed to ask for help. The only truly stupid question is the one you were afraid to ask.