With the way things are these days, I think it is helpful to have at least three layers for long articles. The first is a short summary--the type of thing that pops up in Google searches for instance or the summary we are supposed to write for hubs. These should be clear and catchy and pull people in.
I also think it is helpful, for a long article, to have a one or two paragraph summary of the article at its beginning that is essentially the article in a nutshell. This should also be interesting and easy to digest, because, honestly, these days that seems to be the extent of people's attention spans.
The main article should match the organization of the summary and have clear headings. People can than if interested read the full thing or scan down to a particular section they have a further interest in.
I don't know, I haven't really done this very well myself. It is just something I have been thinking about recently.