CMD+ plus/minus to zoom in/out
CMD+ALT+0 to reset to 100% zoom.
The Little List of Tips and Tricks
Re: The Little List of Tips and Tricks
No idea if I completely missed it or just learned and immediately forgot about it, but (since L12.1) you can now zoom Live's window with shortcuts... i.e without going to the Preferences! 
CMD+ plus/minus to zoom in/out
CMD+ALT+0 to reset to 100% zoom.
CMD+ plus/minus to zoom in/out
CMD+ALT+0 to reset to 100% zoom.
Ableton Forum Moderator