Simple, here are a few pointers below.
Have a space in your home that is completely separate from your family and living space.
Outline your working hours to your Client or Employer. (Let your Client know exactly when you will be available to talk.)
Flexibility works both ways, remember to give and take a little, after all the whole point is that the Clients business expands and grows, making a healthier profit, in the end you will benefit in the pocket too.
Keep talking and stay connected, most relationships break down through lack of communication in an ever challenging world.
Build a good honest, trusting relationship, remember recommendations of your work are highly important in a growing market.
For a different take, I loved this article, you can read it here...
http://www.theguardian.com/small-business-network/direct-line-for-business-partner-zone/how-to-strike-work-life-balance-working-from-home