I’m talking about taking ten minutes to get up and go for a walk, listen to music, have a coffee/cigarette/donut/whatever else. The trick is to keep it at the minimum break length to help, so you don’t waste time.
I would recommend a day as the maximum, go to the zoo, or see friends, or whatever, and then come home and get back to writing. Just don’t let it get in the way of the ‘one a day’ rule.
Risky Move 1 Switch Projects
It might be helpful to jump from one project to another for a while, while it might mess with your enthusiasm it might also give you a chance to get back into the habit of writing, which you can bring back into your main work.
It might also help to have a ‘reward story’ that you can write for fun, once you’ve made some progress on your long term project.
Risky Move 2 Skip Ahead
This is not advisable if there’s any other way to do this, start with all the other options, then use this if you need it but it can occasionally be useful to skip ahead to a cool part, to one of the things you really look forward to writing. Whether it’s the emotional confrontation, the twist, or the big fight scene writing a bit of what you enjoy most can help you get through the connecting parts.
Be warned, that can interfere with finishing the book long term, running out of cool parts to write can make the slog much harder, so again, only do it if you have to.
Remember why you love it.
This is my best advice, sometimes we get so lost in the difficulties and minutia of writing that we forget why we do it. We do this because we love it, because for some of us it’s the est part of our bad days and it makes our good days better. Remember what you love about the world, about the haracters, about the story that you want to share with the world. Take a moment to be happy that this is something you can do, something you enjoy, and remember why you value it.