My two cents... come up with a concept that is MODULAR. I think ACE was extremely successful because it appears (to me anyway) to have been constructed in a modular fashion. That way you can begin with the simple components, and then iterate it through. Sahrani Life, from what I can tell, appears to have grown along the same lines. Have a grand goal - but break it down into workable components underneath that. Keeps motivation up, and makes the work more achievable.