For people who work from home, one of the biggest mistakes is to think it's going to be so fabulously easy. It actually takes a lot of self-discipline. You have to be a self-starter to work from home.
The first thing I would recommend is to set regular office hours, just like you would if you worked outside the home. Then, be disciplined about keeping them. If you say you're going to start at 8 a.m., start at 8 a.m.
The second thing I would recommend is boundaries. Give yourself a lunch hour like everybody else has, so you do have time to be distracted and read or walk, or throw a load of laundry in. Build some time into the day where you can actually do that.
Then make sure you know what time you're going to leave at night. One of the great things about working from home is that you can work anytime you want, but that's also one of the downsides. It's really easy to turn into a workaholic if you work from home.
I highly recommend having a separate work area so you're not in the living room or the kitchen; an area where you can be away from the rest of the household and stay focused. Make sure there's not a TV around. Personally, I do not answer my home phone during the day. I pretend I'm away at an office, so I have a separate line that goes into my office. I take business calls during the day and return personal calls during the evening.