From what I’ve seen and from the examples I collected I believe spacing between columns and regular breaks make it easier to read. If the words create a block of continues text then it can be difficult to read. A clean simple font is needed for legibility.
Images help the balance found on the page and if no image present then just empty white space or even a shape behind some text can create tension and the interest to carry on reading. Having the page split with different columns is also effective so for example the top half of the page has 2 columns and the bottoms half has 3 columns. A good size margin is also important to border the entire page and help creates focus. Colour and bold headings can also help the overall read.
I think when creating a layout, it needs to be designed like any other design, considering white space, tension, contrast, etc. The words on a page need to create a flow and need to differentiate itself from the sentence above or the paragraph before it. Symmetry and rigidness can cause boredom and a good example to compare is an article with 3 symmetrical columns compared with an article with 3 columns but with descending heights due to an image on the page.
I think the skill is in pulling back and taking in the page as a whole, noticing to where the eye leads and what shapes are created through the blocks of text.