I learned something from my Dear Husband, and he really is more DH than a DuH :-). When he wants to get something done, he does it — he powers through it like a chainsaw (i.e., sometimes there is collateral damage), but the task gets done. Me, on the other hand, I am a “multi-tasker”. My tasks are always “almost done” — but seriously when is cleaning the house, doing the laundry, or grocery shopping ever “DONE”?
Okay, here’s what I’ve learned. If you wanna get something done, do it at the expense of all others. Some people refer to it as “laser focus”. Whatever. Just do it (like the Nike slogan). Yeah, there are exceptions, but even a house-fire should derail laser-focus.
So, if you have a book you wanna write, make time and write it. At the expense of the kids??? Well, to a certain extent, YES. Let the kids entertain themselves for two hours while you write a couple pages. What “the extent” is, is up to you. You just have to commit to actually writing that book, doing that craft, or learning that language. Whatever you want to do, do it. It will come at the expense of something else, but that is the cost of opportunity.