I work from home also. It does make it harder to avoid being sedentary particularly when you mostly work from a computer.
One thing I did was to build a simple treadmill desk so I could walk on the treadmill while doing work (I put my notebook computer on the treadmill desk). This does let me at least not sit all the time.
Another thing is to put structure into your day. Set goals to do certain things. For example, I have goals to average a certain number of steps each day. I don't always meet the goals, but it does help to have them.