Garamond is a serif font. Are you saying that you're switching to a sans serif font for a novel?

There are many, many serif faces that work well for novels.* (ITC Garamond, I would say, is unfortunately not one of them.) The choice is an artistic as well as a practical one. Choose something that speaks subtly to the feel of the novel that you are trying to capture in your design. The same goes for size and leading — that's the art of typography, and as the designer you should feel confident to trust your instincts and use your visual judgment. That said, as a starting point, 10 point type on 12 point leading is standard, or maybe even a little smaller, for novels. And just to give you some possible leads, from several different styles and periods: Minion, Garamond Premier, Electra, Palatino, Baskerville, Jenson, Dolly, Stone, Caslon, Quadraat, Mrs Eaves, etc. etc. etc.

* I think you meant serif, not sans.

Sorry I meant Serif!
And thank you very much for your suggestions. I'll try out some of those fonts and try in 10 point type (I was using 11pt so far)
Thanks again

"10 point type on 12 point leading is standard, or maybe even a little smaller, for novels."

That's a questionable statement, from my point of view. An optimal size and leading ratio differs from one typeface to each other, and depends, among other things, by the instrinsic traits of each typeface. I mean, setting a text in Miller on 10 points will give you a *very* different result than, say, a text set in Adobe Garamond in the same size. Instead I would say, from my limited experience, that 11 points is a better readable size for novels, esays or poems. So the first advice is: do some layout tests with serifs with different qualities and features, print the pages and then proceed with gradual adjustments.

How about a sans serif? http://typophile.com/node/16931

Don't use a sans for very long text. ITC Garamond is a joke (although it can work very small, tracked). Off the top of my head: try Paperback. But: what Joshua said - what's the novel about?

hhp

Amazing, I only read the post, without comments, in the rss feed and was immediately thinking Paperback, too.
I always wanted to use it, cool italics plus optical sizes. I guess it could fit for a very wide range of topics.