I’m a big advocate for the hyper key. This idea was first introduced to me by Brett Terpstra and involves mapping Shift-Control-Option-Command to the caps lock key. Using the hyper key opens your keyboard up to a ton of new easily triggered shortcuts.
I’d never considered this before, but what a great power-user idea. Take a key very few people use (Caps Lock) and make it a new modifier key for keyboard shortcuts. It’s much easier to press Hyper-S than it is to press Shift-Command-Option-Control S.