Font size for your main body text is the one you've probably thought about the most. You may decide to deliberately use a large font for the visually impaired, but if not then take a look at a commercial novel and compare it to a printed page of yours. The biggest error I see is using too large a font. This makes your book more expensive for readers (or lowers your profit) because it'll increase the length of your book, and it doesn't look professional.
I used Garamond 10.5pt in my book, and the book is 331 pages long (plus front matter). When I go to 11pt, the book is 360 pages. Just half a pt size adds 29 pages! At 12pt, the book becomes 415 pages long.
The problem with too small a font, other than being harder to see, is that the human eye finds it hard to track a line with too many words on it. It loses its place. That's the reason text books, with pages twice the physical size of novels, are set in columns.
How to find your words per line? Highlight 10 consecutive full-length lines in your novel (i.e. from the middle of a long paragraph). Check the word count (go to Review > Word Count), and divide that number by 10. Ideally you want around 11-13 words per line, otherwise your font size may be too large or too small.
Look at the books on your shelf and measure them to pick your book size. (You did, I hope, choose the book size before you started Word formatting.) Paperback size is increasing in recent times -- a trend I hate because it makes the book harder to hold and more expensive, but the idea I believe was to replace hardbacks and make the larger paperback look more important. To get 11-13 words per line, your font size may have to increase if you've chosen a wide book.
The font set for your body text may seem like a super-easy decision, but there are various things to consider and I'll talk about that in my next post. Don't forget that Times New Roman, for example (and which I recommend against, as out of date), will give you a different number of words per line than the same pt size of some other font. I like Garamond because it's round and friendly, while not being in any way trendy or weird.
Header and page number
I like to put the page number in the header to avoid having a footer at all. I then make the footer a little shorter and get one extra line of body text per page, which saved me 8 pages in Little Sister Song.
Look at a few commercial novels to see what they put in the header. There may be nothing but the page number, but it's more usual to print the author's name on the left page, and book title on the right. I would avoid putting chapter headings in the header (except for non-fiction books) because that requires a new section for every chapter and just adds to your formatting battles -- if, for example, you have 40 chapters and later decide to change the header formatting in some way, you'll have to change it 40 times. My books have only two sections: front matter and the rest.
Once your book size is chosen and you've set up your page layout (page size; mirror margins, which leaves a wider gutter to allow for binding; and header & footer height), Word expects you to create a different left and right header. As mentioned above you'll need to add a section break after the front matter, right before chapter 1. In Word 10 this is found under Layout > Breaks >Section Breaks > Next Page.
Next, double-click in the header on a left-hand chapter page (not front matter page) and make sure "Link to Previous" (on the Header & Footer Design menu) is not checked. You'll be centering your author name, but don't use the paragraph alignment tool for this. Instead, set a centered tab. First, with your cursor at the left margin, add a page number at "current position". Then tab to the center and add your author name.
For the right-hand page, set up a centered tab and a right-aligned tab. Tab to the center and type your book title. Tab to the right and add a page number at "current position".
Highlight any page number and set it to start at 1, if it's not already doing so:
As for the header font, I prefer something different from the body text, including the option of a sans-serif font. In my case, I felt all-caps looked best and simply used my cover font, but you could set the text in plain or italics (not bold!). The size of the font should smaller than the body text, so it looks clearly less important and the reader won't notice it. The page number can be a little larger to make it easy to see. For my page number, I used the body text font.
The front matter itself should have no headers, footers, or page numbers (again, unless it's non-fiction, in which case front matter can be extensive and is often given lower-case Roman numeral page numbers that restart at the first chapter).
If you want to see how facing pages of your book will look, zoom out until you can see two pages on the screen. In a printed book, chapter 1 always starts on page 1, which is always a right-hand page. However, Word will display odd pages on the left. To make Word display odd pages on the right, add one blank page to the very start of your file (simply move the cursor to the very top and click CTRL+ENTER to insert a page break). Don't forget to remove this blank page when you're done. Word now displays the two pages on the screen as they will appear in your printed book:
Here's a tip for viewing your book after you convert it to a PDF (assuming you do), and open it in Adobe Reader. Choose View > Page Display > Two-Page View. In the same sub-menu, make sure Show Cover Page in Two Page View is checked.
This makes the software display the cover page as a right-hand page, and thereafter the odd-numbered pages will appear on the right as in the final book. You can then scroll through the book, seeing one entire double-page spread at a time, and get a feel for how the finished product will look.
If you're enjoying this series and finding it useful, please share so others can benefit, and comment if you have questions or to let me know how you go about the process.
Nitty-Gritty Formatting for Your Indie Print Book - intro
Hard and Soft Section Breaks
Font Sizes Part 1
Font Sizes Part 2
Body Text Font Choices
Making Word Do What You Want Part 1
Making Word Do What You Want Part 2