I learned that Editing is not the same as Proofreading and that Proofreading should happen only after Editing.
Editing is moving stuff around and adding stuff to make the story stronger and increased emphasis where you want it. That takes me sitting down for longish periods of time to get into the story.
Proofreading is just checking spelling, grammar, word usage and continuity. That's easy and can be done in as little as 30 second chunks.
This makes things a whole lot harder. I'm having trouble getting enough time together unfettered so that I can get into the story and be productive. Please wish me luck.