Clarity is achieved by providing information in a predictable order.
General Background. Introduce the general area of science in which your project takes place, highlighting the status of our understanding of that system.
Specific Background. Narrow down to the sub-area that your paper will be addressing, and again highlight the extent of our understanding in this sub-area.
Tip: Give your readers the technical details they need to understand the system –nothing more. Your purpose is not to showcase the breadth of your knowledge but instead to give readers all the tools they need to understand your results and their significance.
Knowledge Gap. After discussing what we know, articulate what we do not know, specifically focusing on the question that has motivated your work. The prior two components should serve as a set-up for this question. That is, the question motivating your work should be a logical next step given what you’ve described in the general and specific background.
“Here we show…” Very briefly summarize your methods and findings. Note that you may end this section with a sentence or two on the implications/novelty of your results, although this is not essential given that you will more thoroughly address these points in the discussion section.