What question do people curious about writing ask more than any other? Well, besides, "Where do you get your ideas?" (And besides, "How much money do you make?") I'd say that the #1 biggie question is: How do you find the time?
By now, I've juggled writing time every way there is to juggle it. When my kids were little, I wrote nightly from 9 to midnight. At times I tried writing before they got up in the morning. Glad to finally become a daytime writer when the youngest started school, I may have had the best of all worlds when I was "home with the kids" yet had most daytime hours to myself.
But then I began teaching, by correspondence. Still at home and able to devise my own schedule, I tried writing mornings and teaching afternoons; teaching mornings and writing afternoons; teaching three days and writing two, the particular days of the week shifting now and then; teaching during the week and writing weekends; writing evenings -- and sometimes just plain all of the above.
Writing is funny. Not funny ha-ha, but funny peculiar. People often expect their writing to live on the edges of their lives, yet it requires a fair amount of immersion. Regular writing, reading, and market study are the three basics, but most publishing writers also take classes, study writing books, attend conferences, join professional organizations, do considerable topic research, network, read and comment on blogs and message boards, maintain a website and blog, and continue to read, read, read. And when you finally publish, promotion and speaking engagements enter the picture, as does producing approximately a book a year. Few career writers put anything other than God, family and day job ahead of writing. Hobbies or an active social life, if there's room for them, come after.
So, you're saying, "Okay, I get that I have to make time, not find time. How?" Try thinking in terms of a balance between regularity and flexibility. Can't write on a regular schedule? What if, each weekend, you schedule the upcoming week's writing? JUST the coming week. Block out those times on your calendar. When the time slots arrive, WRITE. When the next weekend comes, again block out your writing times for the coming week. It doesn't matter if they bear any resemblance to last week's writing times. It only matters that they mesh with what's on your plate for the week in question. Regularity feeds your momentum, and though we may seem to be crawling forward at times, books get written.