Read Backwards
Sometimes if I’m reading something difficult to understand or written in an uninteresting way I’ll skip ahead to the end of the chapter, or perhaps just skim ahead several paragraphs until something looks interesting. Then I’ll read one paragraph at a time in reverse order. I think this helps you focus by forcing you to guess what the writer’s thought process is, and it can also help to know in advance what point they’re working towards.
Alternatively, write backwards. Write in such way that reading backwards isn’t more engaging than reading forwards. The reader can probably handle it if you start with the conclusion. Having said that, I’m not sure what the best order is. Maybe conclusion then motivation, then explanation why conclusion solves the motivational problem? Maybe I’m missing some more parts? Maybe motivation and explanation should be broken into pieces and interleaved with increaing verbosity?