Optimal line length (typically 50 to 75 characters), generous line height (around 1.5 to 1.6 for body text), and high-contrast text-to-background ratios are foundational. Serif typefaces remain the default for long-form reading, though well-chosen sans-serifs can work equally well when set at appropriate sizes.
Single-column layouts with a comfortable maximum width, pull quotes that break up long passages, and supporting imagery placed to complement rather than interrupt the reading flow define best practice. Progressive disclosure through expandable sections or chapter navigation helps manage longer pieces.