It's largely a matter of lateral thinking and metacognition

Like tripping over a bucket isn't going to make you shout eureka! But you're thinking on the problem, and you remember seeing a seller carefully packing his things up for the day into neatly sorted boxes

(Or sometimes you do trip over a bucket, which reminds you of the seller)

You take the root concept, sorting things using a number of containers, and then you deconstruct and reconstruct pieces of the pattern to reapply aspects of it to your problem