1. State your theme and your reasons for its choice. (In other words: make it quite clear to your readers what you are going to write about, and why you decided to write about it.)
2. Say what you have to say about it.
3. Give the conclusions to be drawn therefrom.
Here, as in the case of fiction, it is desirable to get right into your subject quickly, never "side-tracking" the readers' mind on to a subsidiary topic until they have a firm hold of your main theme. Ruskin was particularly tiresome in the way he would turn off at a tangent, and start talking about some minor matter, before the reader had grasped what subject he was proposing to deal with.
After you have turned your theme inside out, in the second part, and told all the points about it that you think will be new to your reader, make your third part a climax, in that it works up to a definite conclusion.
It does not matter what the subject of your article, broadly speaking it should be built on these lines, since this is the form in which the human mind seems best able to take in information. You cannot expect people to follow your descriptions, your arguments, or your objections, if they do not know what you are talking about; hence the need for a very clear presentation of your subject at the beginning.
And, in order to leave your reader in a satisfied frame of mind, i.e. with a sense of certainty that things were brought to their logical conclusion—also an essential in a work of art—the third section must be primarily occupied with the reasons for, or the outcome of, or the deductions to be drawn from, that which has gone before.
This leaves the middle section of the article for digressions, side issues, or any other form of amplification.
Once the student recognises how desirable are the laws of Form, how they give shape and proportion and cohesion to matter that would otherwise be void and hopeless, he will realise how impossible it is to do good work without preliminary thought, and careful planning. And he will also understand how it is that MSS. which are merely "dashed off" without any preparatory work, those that "just came of their own accord," as the authors sometimes boast, invariably fail to arouse a spark of enthusiasm in the soul of an editor.