As we noted yesterday, we're working on a guide that will give you more insight into how you can avoid errors and pitfalls in your ebooks, whether you're building them yourself or someone else is building them for you. We'll send out the full guide to our newsletter shortly, but for now, here is an excerpt on production errors—what goes wrong as you prepare your manuscript and convert it to epub and mobi files:

Error: Difficult files pre-conversion
Word documents will always be preferable over PDFs, which are meant to be locked down. In Word documents, the text is encoded, with all of the characters properly spaced out. Word files are easily editable for an author converting a manuscript on her own and for ebook building services (who may charge extra to convert PDFs).

Error: Making images too large
Images should not be so big that the ebook takes too long to download, but they should be big enough that a reader can click on the image, enlarge it, and zoom in (on iPad, iPhone, Kindle Fire, and Nook). The hard limit is 2 megapixels (there are one million pixels in a megapixel). To calculate the megapixels of an image, find the image properties and multiply the length and width. 1000 pixels length or width are recommended to see things clearly on larger screens and the iPad 3, which has a retina display. This size is small enough so as not to increase the loading time and ebook size.

Error: Making the ebook size too large
Not only do large ebook sizes slow the downloading process, some e-retailers have file size limitations. The maximum epub and mobi sizes depend on the relationship an author or ebook distributor has with the retailer. The maximum ebook file sizes are:

• Apple iBookstore—2 GB
• Barnes & Noble PubIt!—20 MB
• Barnes & Noble via distribution service that works with multimedia ebooks—600 MB
• Amazon Kindle Direct Publishing—50 MB
• Amazon via distribution service—650 MB

Error: Copy and pasting URLs to build links
Anchor links—links to other parts within the ebook—are best for footnotes, endnotes, and glossaries. Many authors will start building an ebook with plans to link each section in the Table of Contents to its corresponding text in the body of the ebook. However, eReaders have built-in table of contents that can save authors hours of time building and testing links. Unless you are using an ebook building service or are willing to put a lot of time into building anchor links—a complicated process—do not plan your ebook to rely heavily upon anchor links for a Table of Contents. Some authors choose to forgo the Table of Contents altogether in favor of the eReaders’ built-in systems.

Error: Not testing across all devices
If you hired an ebook building service to build your ebook for you, make sure they test epub and mobi files across all devices for the major retailers. Assuming you want to sell on Amazon, Barnes & Noble, and Apple’s iBookstore, test the ebook on a Kindle, Nook, and iPad. If you build the ebook yourself, try your best to test on these three devices. At the very least, test on one, playing with the fonts and text sizes to see how the ebook reflows with each size (see part 2). Make sure that headlines, indents, and other formatting are consistent throughout the ebook. If you have any external or internal links, make sure to test every single one.

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