ENVIRONMENT
He touched on this, but I want to let you know, after 4 years working from home, how important this is.
The environment gives you unconscious cues on how to behave. If you goof off (surf the web, stream, eat, play, etc) where you work, you are "poisoning" that environment, & make it very hard to focus on work next time there.
After "poisoning" several places in my house, I've setup a workbench in the garage, & ONLY work there. Meaning, if I'm working there & need a break, I LEAVE that environment, so as to keep it clean. Then, when I return to the environment, it's easier to focus & get things done.