A perfect paragraph isn’t very noticeable. However, when you learn the rules of a properly typeset paragraph they become a very beautiful thing. These rules are meant to be applied for print paragraphs, since responsive displays, browser rendering quirks and device limitations make several of these rules almost impossible to implement on the web.
If you ever want to break the rules, you must know them first.
If you decide to typeset a left or right aligned paragraph, you must make sure the edges are properly ragged. What this means is the ragged edge has a consistent flow, with lines that alternate from longer to shorter down the length of the column. Otherwise the paragraph takes on a bizarre, distracting shape.
A justified paragraph has completely even edges, great if you don’t want a ragged edge. Text editors can create justified paragraphs automatically by adjusting the space between words, which can actually look really awful. If you’re going to typeset a justified paragraph the minimum number of characters per line should be no less than 60 and the word spacing needs to stay relatively uniform throughout.
Center axis paragraphs have a more abstract ruleset to typesetting. It’s important to be aware of how they appear visually, the shape must be appealing and have a form of some sort. The lines can also be broken up by meaning, different phrases getting their own lines to communicate gravitas.
When typesetting the start of a new paragraph, you can use a first-line indent or a space between paragraphs. With a first-line indent, consistency is key. They must never vary in width from paragraph to paragraph. When using a space between paragraphs you must never include a first-line indent as well.
Widows and Orphans
A widow is the final line in a paragraph that only contains a single word, while an orphan is a stray line of text that appears at the top of a page, breaking horizontal alignment with the opposite page. You can remove widows by adjusting paragraph width, tweaking the space between words or forcing a line break. With orphans you can force a page break in the opposite page so that there will be more than one stray line at the top.