It comes from my standard advice for planning a PhD thesis (but probably works just as well for scientific papers, essays, etc.). The key trick is to plan your argument in six sentences, and then use these to structure the entire thesis/paper/essay. "The drug cured 1/3 of the infected mice, another 1/3 were not affected, and the third mouse got away." TABLES AND GRAPHS 1. If you present your data in a table or graph, include a title describing what's in the table Enzyme activity at various temperatures not "My results".) For graphs, you should also label the x. Use concise terms. Instead of: Write: prior to before due to the fact that because in a considerable number of cases often the vast majority of most during the time that when in close proximity to near it has long been known that I'm too lazy to look up the reference 5. A standard format is used for these articles, in which the author presents the research in an orderly, logical manner. This doesn't necessarily reflect the order in which you did or thought about the work.
State the problem you tackle. Whats the key research question? Again, in one sentence. (Note: For a more general essay, Id adjust this slightly to state the central question that you want to address) Remember, your first sentence introduced the overall topic, so now you can build on that, and focus on one key question within that.