Would you mind talking a little bit about your writing process and how you managed to bring such an ambitious idea to fruition?
The most accurate, if least enlightening, answer is "by sticking with it."
In this case I realized I wanted to do a fantasy with dinosaurs in it. That required me to start building an appropriate world, ecosystem, and human society (actually, societies) to fill it out and lend it verisimilitude. Which of course required extensive research into all kinds of bizarre areas - which I usually find fun.
The characters began to come to me, and with them my story. Occasionally I'll think of a story first and then imagine characters to live it out, but usually my characters help me realize what my story is. And they always inform the way the story turns out.
From there I fleshed it out into a (probably overly detailed) synopsis, and began to fill it in.