This is a key ingredient to writing effectively. You must increase the velocity of your writing.
Some people 'free write' or do 'freefall writing'. Some people write morning pages ala Julia Cameron. (I've been trying those myself, but I am not a morning person so my pages tend to be quite negative.)
It is all related. The key to get writing, it to git to gittin' it and git writing.
Oh would that we could all do that, right?
It's not easy. I've sat there, staring at the blank screen, being mesmerized by that blank, white space that seems to be swallowing my confidence and drive whole and without pausing to chew it. The only way I've found is to make yourself write. It may be crap. It probably will be crap.
There have been many times that I've started off with:
"Put witty beginning here that pinpoints the market challenges."
"..something here about background info..."
"In XXXX, Paul began buying up property around WHERE THE HECK DID HE LIVE and building LOW INCOME?ECONOMICAL?..."
"something about the horses blah blah blah.."
As I'm writing my book, I often come across parts that need further investigation. But I know that if I stop to research it, I will find myself surfing and wasting time. So I highlight an area and write CHECK or RESEARCH in block lettering so I won't miss it when I'm editing or reviewing what I've written.
You must increase the velocity of your writing if you ever want to get writing with kids around. You may only have five minutes while waiting for school to get out, or ten minutes when both kids are blessedly down for their naps, or a half hour before everyone gets up.
If you ponder and wonder about the perfect way to write that opening sentance, you risk losing important minutes - seconds even! - of writing time.
By increasing your velocity, you increase the word count and increase your odds of finding the perfect wording, the perfect sentance. Sure, you'll have to prune and edit away the crap, but you have something to work with. You have a body of work, fat, plump and ripe for the carving. It can be hard to carve a blank page.