Just like writers get writer's block, designers get designer's block – whether it's grasping for creative inspiration or struggling to understand the scope of the problem. There are a lot of techniques for overcoming designer's block, but it's often difficult – at the time of being stuck – to remember them. After all, if you remembered then you probably wouldn't be stuck in the first place.
I get stuck often, so last year I started carrying blank deck of cards around with me. Whenever I find something that resonates with me – whether it's a design principle, philosophical concept, or words of inspiration – I record it on a card. The card gets added to a deck. When I get stuck I pull out the deck, shuffle it, and select a card at random. If that one doesn't speak to me I shuffle and repeat again.
The idea of using cards to help move the design process along isn't new – in fact, I first picked up the idea after reading Jesse Schell's The Art of Game Design: A Book of Lenses. Schell's book comes with a deck of pre-made cards that contain plenty of game design wisdom, and is organized by themes like emotion, surprise, and curiosity. Figure out what your game's currently lacking, and pull out a corresponding card.
But we all get stuck in different ways that are specific to our own personalities and blind spots. Making my own deck of cards is incredibly useful because it speaks to my own blind spots and helps me get unstuck.
Maybe some day I'll share them.