Also to add, you can shrink down the font size with paperbacks to help with the economy of paper space. And the margins. Putting together a paperback can be a weird art. It's yet another thing we do with a learning curve that has nothing to do with writing.
Don't touch the margins, shifting down the font size by half a point is good, but white space is actually good in print books.
Firstly, it's been a while since I visited the forum, but it's good to be back.
My WIP has short chapters which produce a lot of white space between them. Obvously this isn't a problem with the e-book format, I can just make them flow, but the problem is I'm creating a print version.
Probably the most obvious solution is to write longer chapters so that they almost fill up a page, and create less white space.
Another solution might be to use a larger typeface, but realistically 12 point is about as large as I can use.
I'm guessing, and this really is a guess, that lots of white spaces between chapters are irritating for readers.
It's also less cost effective than filling the entire page, because I'm paying to have these white spaces 'printed.'
I might be paying to have a 300 page book printed of which only about maybe 80% is actual text.
White space is good for print and here's the thing when it comes to cost. Unless you are doing a pocket paperback and using offset printing, trades can cost up to $22 or $24 without people being too upset.
There are some good ways to cut down on the print length, and minimize the effect of shorter chapters. The easiest way is not starting each chapter on the right facing page. There is no rule or convention about that, despite what most indies claim. Check out any book in a bookstore or library and just as many (if not more) start on both facing pages. The almost as easy way is to shrink your trim size down. Yes, this will increase the pages, but it will decrease the white space. Again, despite what everyone claims 6x9 is not the traditional size, it's closer to the 5 1/4" x 8" for trades. Finally, changing the typeface can make a huge impact. There are some typefaces better suited for some genres (I wouldn't use Sabon in a thriller) but moreover, there are some typefaces that are designed to be space efficient. Baskerville is good for that, but you want the right Baskerville and there are a lot of version out there. Gandhi Serif is a free typeface that does well at smaller point sizes (8-10), which would conserve some space.
People need places to put their thumbs when the read a book, so you want to have decent margins on the outside and bottom. You can scrimp a little on the top, but then shrink down the font size of the running head.
If you're really struggling, drop me a PM and I can see if I can help you with more specifics.
