Don’t “find time” for your writing, carve out time for it.
Don’t just say that writing your book is important, make it a priority.
The best way to do that is to schedule the time for your writing and other important things. Put those important things on your calendar first when you plan your week or your month.
I call those things “appointments with myself” and once they’re on the calendar, they’re sacred. One of my clients called her writing times, “appointments with success” and her designated time for family, “appointments with happiness.” You can call those times anything you want. You can call them nothing at all.
The important thing is to set aside time for the important things before you start scheduling all the other things. Stephen R. Covey called that “putting the big rocks in first.” Check out this six minute video for a delightful explanation.