1. Clean up! And I don't just mean around you, although that could also apply. I am referring to your work files and folders, physical and virtual. If you know where to find what you want, you lose less time hunting it down. It usually is just small enough a break, and knowing that you completed something might give you enough impetus to work on your writing project.
2. Time yourself instead of giving yourself time. When I know I have the whole day ahead of me to work on a story, I take all day to complete it. But when I time myself and give a story only limited hours to be completed then I work faster and get everything done in shorter spans of time. Try it and let me know if it helps you.
3. Submit away. I used to be the person that tried allowing time every few days to submit ideas and pitches but invariably those times never rolled in as I would always put away that exercise for later. Now I just submit as and when a call comes through or I feel an idea brewing in my head. Just the excitement of that keeps me going.
4. Always a student. When you learn new information, it induces a new wave of possibilities irrespective of the subject or area. I like to constantly keep myself in that learning mode so I can polish my techniques and skills, pertaining to my profession of course. If I find a local class or networking group that would help I join it and learn what I can. If there are workshops or conferences in my city or industry that will help me be a better writer or editor then I sign up for those as well.
5. Motivational quotes are a no brainer. Especially if you are a writer or editor. It is important to be surrounded by positivity and affirmations when the environment you are working in is one of isolation. I enjoy reading Monday Motivation by the Renegade Writer, or anything by Marc and Angel and even Chris Guillebeau.
And this last one might not work for all but sometimes it helps to not be working on a specific project for someone else but just on something you want that is not defined by a third party's requirements. For instance, that book of poems describing your childhood or the short story collection you want to submit to a contest someday. Those help keep you driven and challenged time and again.
How do you stay motivated at all times?