I can't! That's just it. I can't be the perfect wife, mother, home-school teacher, writer, friend, etc. Not gonna happen, no matter how much I feel it should.
I can't write if I'm distracted by other things. I can't write if THINGS are pulling at me from every angle. I hear writers complain about time. "Not enough time to write today," they say.
Hmm, is it time or are they just pooped? Are they too tired from all of their other responsibilities to lift a finger to type? Have these writers had an energy drain? Being everything to everyone saps energy you need to create your best seller.
Save some of yourself for your writing. Say "no" for once. Give just a little bit less. It will be okay. It's for THE book, after all.
Don't answer the phone while you're writing. And don't feel bad for that. Don't go to the door. Believe me, the salesman will return. :)
I read where an author (I forget who) doesn't have caller ID. When asked why, she politely said, "That wouldn't be nice for my book." Pretty cool huh?
Don't feel guilty about your all important writing time. Feel good about it. :)