1) Set aside "work hours" for your writing* at home, even if these differ from day to day. Decide on these hours (or minutes!) ahead of time, perhaps the night before. If you're dependent on other factors, such as a small person's nap, don't do anything else but write while that small person naps.
2) Just because you're "only at home writing" doesn't mean you have time to run errands, take kids to every activity, be there for every delivery or repair person's appearance. Tell your people you're not available. They're smart. They'll figure out alternatives.
3) Don't answer the phone.
4) Don't put off your writing until the house is clean.
5) Don't blame others when they don't take your work seriously. You must take your work seriously before they do. It's not about how much you are or aren't getting paid: it's about respecting your vision.
Mostly it's women who find themselves juggling home caretaking and/or childcare along with their creative work. Whether you're male or female, remember you're not superhuman. You can't do it all. Your choice to be a creator at home is something to be proud of.
And don't bother about whatever's smoking on the burner.
*Or maybe you're doing photography, scrapbooking, songwriting, pie-making.