When I worked in professional digital publishing, there were certain formatting mistakes that weren’t allowed on publications going out of our department to other departments or our company’s clients. I frequently see ebook authors making these mistakes, along with a few other common errors.

To me and others aware of publishing industry standards, these mistakes are marks of an amateur. If you want your ebooks to look more professional, here are a few common mistakes to avoid.

(I should mention that in this article, I am talking about ebooks produced in PDF format. Some of what is said here will not apply to ebooks produced in mobile reader formats such as Kindle, though there is some overlap that does apply to both types of formats.)

Don’t Blend Your Cover and Title Page with Your Body

In some ebooks, it’s difficult to distinguish the cover from the title page, or either from the body of the text. Make these distinct by using page breaks in the appropriate places. For a model, look at the way the first few pages of a printed book are laid out.

Don’t Skip Your Table of Contents

A table of contents makes your ebook easier to navigate, which makes it easier to read. Do you reader a favor by including one.

Don’t Use Multiple Fonts in One Document

Just because Microsoft Word lets you use hundreds of fonts doesn’t mean you should use them all in one document. Each font has been professionally designed with its own standardized features for the shape, height, and width of the letters, as well as the spaces between letters. This design is intended to make the font readable to the subconscious eye. Mixing fonts destroys this design and can make your font hard on your readers’ eyes.

Stick to one font per document as a rule of thumb. The only major exception is for your main title page, where you can use a different font for aesthetic reasons. But don’t alternate fonts in the body of your ebook.

Incidentally, for on-screen viewing, a sans-serif font like Arial has traditionally been easier to read than a serif font like Times New Roman. However, as screen resolution quality has improved, some newer serif fonts have been designed to be readable on computer screens and mobile devices. This will undoubtedly continue to develop.

Don’t Make Body Fonts Too Small or Too Large

In our department, where we were usually creating documents intended to be printed out, we used 12-point font as our default size. We never used fonts smaller than 11 points, except for very special exceptions. Smaller than this became hard to read when a document was printed out. At the other extreme, as the body text became larger than 12 points, it quickly became too loud for the eyes.

Now when applying this to ebooks, it’s important to remember that ebooks are primarily intended to be displayed on-screen in PDF format, which translates font point sizes into percentages. In this context, 12 to 14 points for the original word processing document before conversion to PDF is a popular size range. There is some variation for audience and taste, but generally, bigger or smaller font should be reserved for special uses such as headings or footnotes.

Don’t Overemphasize Everything

Some ebook authors, influenced by copywriters, tend to bold, italicize, underline, color, and highlight half the words on the page. But top copywriters agree with professional publishers that when you emphasize everything, it loses the effect. Save your emphasis for truly important passages if you want to preserve the impact.

Don’t Leave Long Text Blocks Unbroken without Breaks and Headings

After a while, a long block of text gets hard on the eyes. Spare your readers eye strain by using shorter paragraphs and more headings between groups of paragraphs.

There is no absolute rule here, but there are some general tips I tend to follow that you may find useful. For a full page, I try to include about three headings, providing of course that it makes sense in context. For a paragraph, I start trying to wrap it up after about three lines, and if I find myself going much over five to seven full lines, I consider finding somewhere to insert a break for a new paragraph.

Don’t Leave Words Hanging Before or After Page Breaks

I often see ebooks where a heading appears at the bottom of a page but the text it introduces doesn’t appear until the next page. Another version of this phenomenon is when a single word at the end of a chapter spills over onto a new page and the rest of the page is blank. This is ugly.

Avoid this by planning your page breaks more strategically. Sometimes you may need to reword a sentence to shorten or lengthen it. Other times you may need to insert manual paragraph breaks or a manual page break.

Avoiding these mistakes will make your ebooks look more professional. Equally importantly, it will make them easier for your audience to read. Their eyes will appreciate it.