I wanted to do an "On Writing" blog post today, but my son is sick, and I am feeling it too, so I'm going to be lazy and direct you to a really great blog post about world building. The link will direct you to the fine people at Paper Lantern Literary. This post is really thoughtful and heaped with great advice for writers.
I shall dig my way out of the mountains of Kleenex in the next day or two . . . or three. I promise!