The jazz trumpeter Dizzy Gillespie famously said that it took his whole life to learn what not to play. The same is true for designing and writing academic works. You need to identify what not to cover in your research, and you must remove tangents peripheral to your analysis or argument. You might have to cut major sections or even chapters. This will hurt. I cut many pages of material in the final stages of writing my master’s thesis, including a number of chunks that I loved but which did not quite fit with my final structure and arguments. A thesis, like any written work, is always stronger when you omit unnecessary sections. Simply place those parts in a separate file and work them up later for a submission to a journal.Man falling while water skiing