If you want to actually retain information you consume, you gotta practice retrieving it from memory, not just re-consuming it. You have retained information if and only if you can regenerate it from memory. So naturally that is the exercise that must be practiced. Yes, it is also helpful to make connections between isolated pieces of information. Yes, those connections are themselves information. Yes, if you want to retain the connections, then you have to exercise their retrieval, not just re-consume them from an external source. Yes, this also applies to connections between connections. Yes, this also applies to skills, concepts, procedures, applications, etc. If you want to be able to generate it from your head, then you gotta practice generating it from your head.