“Learn to think like a designer, not a player.”
You’ll hear this a lot from game developers giving advice to would-be designers. And it’s not wrong … but taken at face value, it leads to being a sub-par designer. There’s no value in mimicing what you think a stereotypical designer would do.
Better advice: “Learn to understand how different types of players (including you!) experience your game, and analyze that like a designer.”
Not nearly as memorable, but way more accurate.