I went on a task to converting one of my PDF books into a ePub so I could use with my readers and I found out that it is a harder task that it really seems, therefore, with some patience and a little validation and bug correction, you can easily fix all issues.
The first step is to download Calibre. There are other conversion tools online to be downloaded but Calibre does a heck of a good job on converting your file.
The next step is to convert the file and check if it is a valid file for iPad. Let’s use Apple’s iPhone and iPad as a base since Apple’s standards are the worst to be met. For checking if your file will work, go to the ePub Validation from ThePress.org. Upload the epub file and wait for the result. If everything works fine you should get a nice passed score, otherwise it will throw a bunch of errors on the page.
Now comes the hard part. If you see errors on the page, then you need to edit your epub based on the errors that you receive. Basic knowledge of HTML and XML is more than enough for fixing the files. Calibre will not let you edit the epub files individually, so we will need a secondary software for this. Using Winrar uncompress the epub file, just like you would do with a .rar file, and edit the files using Edit+ or Notepad. Once all changes are done, just place them back on the .epub file.
Validate the file again, just as a double check and you should be good to go.
Note: Most of the errors on the report will be easy change, but there is one that is quite hard to understand. If you come across an error saying: unfinished element – you need to make sure that all childs under that element are there. This one usually happens on the .opf file that contains the metadata and epub information.
For more info about epub’s: http://en.wikipedia.org/wiki/EPUB