Holding down SHIFT whilst settings layer settings will set that setting for all layers.
Holding down SHIFT whilst settings channel settings will set that setting for all channels.
CTRl+ALT+ENTER will bring up the screen setup window, this however stops the current output. so we use it mostly when we can't get to the screen-setup button with the mouse (when you have a single screen setup and your output is fullscreen).
all other shortcuts are listed in the preferences.
when right-clicking an effect parameter slider it will reset that slider to it's original setting. This also works on the sliders in the audio section.