Abobe Lightroom is about productivity. The faster you can work, the more time you have for shooting, not editing.
My main three Lightroom shortcuts are very simple:
G – takes you to the “Grid” view in the Library module:
E – takes you to the “Loupe” view in the Library module:
D – takes you to the Develop view in the Develop module:
I switch between these views many times a day – it is amazing how a few simple shortcuts like this can make your life more productive.
Also try F (full screen toggle: tap it three times to cycle through the options) and L (Lights out – ditto).
There are of course many more shortcuts and nice-to-knows: Michael does photographer coaching, both remotely and in person on location: contact me if you are interested.