Productivity is always the biggest issue for me. Let's face it-- my home is full of distractions. My cat, my X-BOX, those bills that need paying, the backyard that needs to be watered, etc., etc. The list goes on and on.
I struggled with this for a while, until I decided to make myself an office environment in my home. My house is fairly small (only about 950 square feet), and as a result we do not have an office. We do, however, have a guest room, which is rarely used by anyone except my cat. We keep it nice and clean, in case of any unexpected visitors, so the room itself was naturally distraction-free. It was an easy thing to buy an office chair and install a fold-away desk on the wall above an outlet. Voila! Instant, cheap, work environment, with a closable door to lock out the rest of the world.
Each day I work from home now, I get up at the same time as I go into the office, I get dressed, showered, and shaved, and sit down at my "work environment" at the same time I'd start the day at the office. I get up for lunch and breaks at the same time I would otherwise. I call it quits at the same time I would if I were walking out the office door.
Here's the final product. Even though the room itself is small, the desk doesn't take much space, is collapsible, and has actually been a nice improvement for our visiting guests, most of whom end up using it at some point.