Up to this point Formatting Tips have been focused on the EPUB format and working directly with the underlying XHTML and CSS. Not everyone wants or needs this level of control over the layout of their book. Often times a book only needs basic formatting such as headings, bold, and italic. There are other easier ways to format an ebook. However, in this case simpler does mean basic.
A very easy way to format an ebook is to start with a plain text file (TXT). Then use either Markdown or Textile to add the formatting. Both Markdown and Textile allow for simple text formatting and they are designed to be converted to HTML.
By using TXT with a formatting syntax you can use pretty much any text editor you want. Markdown and Textile are very simple formats that are much easier to learn than XHTML and CSS. Adding things like bold is as easy as putting a * before and after a segment of text.
I recommend looking at both Markdown and Textile. There are differences in what formatting they support but they both support the basics like bold, italic, and headings. I’ve found Markdown to be easier to use but Textile offers more options.
After adding your formatting to the text it’s very easy to turn the TXT file into your desired final format (EPUB or MOBI most likely). calibre supports TXT formatted with either Markdown or Textile. However, the Textile support is more robust. Simply convert to the output format of your choosing.