With Keynote app, it is never be easier more simple for making beautiful and creative presentations in OS X on Macs. During my study process at my uni, there were many my classmates asking for solution to find find Auto-shrink Text on a new Keynote.
Basically, The text automatically fits when the title or body, text placeholders are used. You therefore can locate Side Layout to find Auto-shrink Text on a new Keynote.
Inspector > Format > Slide Layout
It is just a quick tip but should be useful for users who don’t know yet.