Jen, ever ridden on the back of one? Have you listened to the engine when the driver shifted? That's what you should learn to do, listen to the engine for shift points. Art is telling you true.... the book will tell you to shift sooner than the norm, and you won't be "breaking the bike" by shifting at higher rpms, just don't gun it till it screams then shift, THAT would be bad.
I have told many a rider its a bad habit to look at your rpm or speed when you shift, it takes your attention off your surroundings and your eyes off the road in front of you.
I almost never look down, only to make sure i'm not over the speed limit, most times i'm just keeping up with or slightly behind traffic.
If you are learning to ride, yes, you might have to look to learn the sound pattern and when to shift, but do it in light traffic if you can, or in a large parking lot (took my wife to walmart after 8pm and on weekends real early.
Hope this helps...