Show is better than tell, but that is not the whole of the story. What are some tried and tested ways of conveying a lot of knowledge, understanding or information - not necessarily technical - in a fairly short period of time in a novel? For example, one might have a character who likes to explain a lot, or there might be effective ways to convey knowledge or information while at the same time depicting action.
The knowledge need not have been learnt by a character or the narrator through being formally taught, even by himself. He may have learnt it through acute observation and detailed consideration and analysis, perhaps over a period of several years, perhaps without talking about it much or even at all. This would include life lessons learnt through meditation about experience. I am trying to keep this question general, but particular examples might include
the social geography of high streets and the factors that have determined the architecture and the range and positioning of different kinds of shops
skills that have been learnt largely in practice, with only a fairly small amount of formal teaching, such as the skills of salesmanship or advanced deception
highly honed skills of charming people
a solid and detailed framework for understanding certain types of social interaction or social environment that the character or narrator has conquered by himself.
Rather than just showing that a character or the narrator has this knowledge or set of skills, and how he uses them - that's if he actually does - how might we convey the knowledge to the reader fast?