Q: What do you do when you are struggling with a particular point in your writing?
A: I really believe in writing drafts. My first draft is just to write something to get started, knowing I will go back and re-write some or all of it later. Thus, I always leave time not only to do several drafts, but also to put it aside between drafts so that I can review it with fresh eyes. One of the reasons I do drafts is that, for me, when I find a section that I just cannot seem to get right, the best thing to do is to delete that section and start again from scratch. I write a new outline of my key points and supporting data to try to get the logic clear, and write it all over again without reference to the previous version. Another thing that I find extremely useful is to talk through a tough section with someone, even if I am just explaining my problem and the way I want to resolve it to someone with no knowledge of the subject. Just the act of having to articulate it to someone helps me clarify my logic in my own mind.
(E.g. this answer required an outline of key points, a rough draft, a second draft that was almost a complete restating of the points, and a third draft to make it more concise and meet the word limit).