Here are some tips just for you.

• Understand your work habits. Are you self-motivated. Do you need to be coaxed to "go to work". Are you easily distracted? Do distractions tend to annoy you? Do you work alone? Is it silent most of the time or do you have heavy phones or clients coming to see you? Do you like music in the background?
  
  
• If you will have people meeting with you, place your office near an entrance to the home or create an entrance. My daughter's voice teacher built a complete studio in his garage. Students would enter and leave by a separate door than his front door.
  
  
• Install extra electrical outlets, if necessary, to run your equipment safely. Decide where the additional phone lines and lighting should be in advance. Once installed, does the space still remain flexible as far as placement of furniture and equipment is concerned.
  
  
• Think about storage. Is there enough? Can more be added?
  
  
• Pre-measure all walls, windows, doorways so you know exactly how much space you actually have.  Allow plenty of space for traffic flow.
  
  
• Check to make sure you have not blocked any elements such as vents, windows, closets. Pre-measure your furnishings too to make sure they will fit where you want them. 
  
  
• Make sure your chair supports your back. Make sure your keyboard is placed at a comfortable height. 
  
  
• If you're right handed, light should be placed on your left side. If you left handed, the opposite is true.
  
  
• Make sure window treatments allow you to change the amount of light streaming in throughout the day. Avoid glare by having treatments that control the direction of natural light.
  
  
• Place your furniture so that the ugly computer cables are hidden from view, either against a wall or in a corner.
  
  
• Invest in a large chair mat to protect your carpeting or hardwood floors.
  
  
• If you have cats or dogs, check the vents on your computer (and other equipment) periodically for hair. I have 4 cats and the hair circulates in the air. I was shocked to discover that two of my vents were nearly closed shut by matted cat hair over the 2-1/2 years I've owned the computer. This is not good.