Obvious, but easier said than done. Like the author states, it's a slippery slope into the condition described by the Oatmeal: http://s3.amazonaws.com/theoatmeal-img/comics/working_home/6....

I work from home, and it's amazing how effective it is to simply "dress up" at 8am and "dress down" at 5pm. If I didn't do this, it's easy to fall into the trap of starting at 8am in your underwear and spreading out 8 hrs of work all the way till 11pm. It's fine when you're single, but a recipe for disaster if you are in a relationship.