Couple of quick tips from todays class that I was teaching...
3d model rotate - hold down the Ctrl key and wheel mouse to spin the model.
Cloning - Move tool, hold down Shift. This will duplicate the object, but giving yo uthe option of Copy, Instance or Reference. Instance vs. Reference... Instance you can change any of the object copied and it updates all of them. Reference, you need to change the original, to update the oters.
Save Copy - This saves your scene and adds a number sequence to the end of the file name.