I guess overall I learned how to use the flash. I under utilize it in so many ways. Some of the highlights!! Pardon the pun.
How to use rear shutter to shoot a shot where ambient light is taken into account.
How to use manual settings to control fill flash backgrounds from blowing them out, to balancing them with the subject, to making it go black.
How to really use with multiple flashes for creative effects. Now all I need is three more SB800s!! LOL
Some cost effective lighting umbrellas etc.
Some great white balance tools.
How smart this thing is! AMAZING.
When to still use GN settings even with everything it does!
How to really use exposure compensation in the flash!
How to have a basic gray background and change the color of it!