When you’re dealing with text-heavy documents such as annual reports, booklets or magazines, properly formatted typography can make the difference between something people want to read now, and something they eventually toss in the trash having only skimmed the headlines. Here are a few tips for making your typography a little more readable.
Bump it up
When you’re dealing with wide pages (8.5″ or wider), the text will be difficult to read if you run it all the way across the page (even with a one inch margin on both sides), use auto-leading and hard-returns after paragraphs. 
The default settings used in the image above make the text appear bunched together and generally uninviting to read. Instead, try increasing the margins a bit more (decreasing the width of the text box). Give your text a little air by increasing the leading by at least five to six points more than the size of the font. And rather than using hard-returns after a paragraph, use the Space After feature in the Paragraph panel to increase the space after a return automatically – it’s much easier to fine-tune the amount of space this way. 
As you can see in the image above, not only does increasing the leading make the text more readable, but adjusting the width of the column or text box serves to clean-up the overly-ragged line breaks on the right.
Add more columns
If you simply must fit as much text as possible on the page, try using a multi-column text box instead of one single column. Generally speaking, when I use multi-column text boxes, I only increase the leading a few points larger than the font size, though that’s just a personal taste, you might want to keep the five to six point larger leading. Also, turn on hyphenation in the Paragraph panel to avoid “rivers” of space running through your paragraphs. 
As shown above, the type remains neatly fitted in the columns due to the hyphenation, and the text still remains readable – even though I’ve not given it as much leading as the previous image. 
Finishing touches
When using justified paragraphs (especially in multi-column text boxes), always remember to turn on the Optical Margin Alignment in the Story panel. This will hang your punctuation outside the text box, helping to keep the visual appearance of the justified text intact. Quite frankly, I always leave it on whether the text is justified or not. One other thing to consider is how much text is on each page. Generally speaking, the less text you have, the larger you can make the type on the page. This is difficult to judge up-front because you don’t know how much text will fit on each page, and you don’t want multiple font sizes running throughout your piece. Once you determine that you only have a half page of text for each page in your document, consider upping the font size by a point or two (don’t forget to increase the leading accordingly). I typically never go over 14 pt. text for body copy though, and it really depends on the font you’re using as to whether or not it looks good. As with all rules, the ones I’ve covered here are meant to be broken. Every situation is different, and this certainly isn’t a complete list. There are plenty of other things you can do to help improve the readability of your text documents – just play around with it and ask your peers to look at a few comparison pages to get their opinion.