For most books, the most important component is the text, which, first and foremost, should be carefully edited and proofread to minimize or eliminate grammatical, typographical, spelling, and other errors. Your text should also be readable. You undoubtedly have a writing style all your own, but you must also consider how your writing will be understood by your target audience.
Your text will need to be formatted properly. This will involve dividing the text into chapters, placing any images at appropriate locations within the text, adding headers and footers, and much more. Traditionally, headers are comprised of the book title on the left and chapter title on the right, but this can be modified to suit the author’s needs and preferences. Page numbers can be placed at the top of each page, near the outer edge, or at the bottom, either in the center or near the outer edge. The textual content is usually single-spaced, with little or no extra space between paragraphs.
Chapters should begin on the right-hand side. If a chapter ends on the right-hand side, the next page is left blank. In addition, headers and footers, except page numbers, are usually absent from the first page of each chapter (this is also true for pages containing full-page images). For the first page of each chapter, the text typically starts further down the page than on standard pages (i.e., the first page of each chapter has a larger top margin).
All professionally produced books, especially those intended for sale, should have front matter. This is content that appears before the main body of your book and should include, at minimum, Title, Copyright, and Contents pages. You may also wish to include additional components such as a Preface, Introduction, etc. Following the Contents page, most front-matter pages are numbered with lower-case Roman numerals (i, ii, iii, iv, …). The main body then begins with page 1.
Many books also contain back matter. This is content that appears after the main body of your book and may include an index, credits and references, etc. Like the main body, back-matter pages are usually numbered with Arabic numerals (1, 2, 3, 4, …). Page numbering continues uninterrupted from the main body through the back-matter section (e.g., if the main body ends on page 295, the first back-matter page is 296).