"If you can't explain it simply, you don't understand it well enough."
A lot can be stored in a human brain, but if we stored everything up there, it would get too "cloudy" very quickly. My recommended approach to a relaxed, efficient learning experience is to understand the broader picture of a topic, be able to analyse its patterns to break it down into little pieces and apply it to a given context. Language learning is no different.
This resource and link list is my growing rescue centre, it helps me a lot and I hope it is useful for you too.