Effective way to learn is repetitive and consistent learning

What you learn, you forget 50% of it within 60 minutes and only retain 20% after a month.

The best way to learn and retain longer is reviewing/revising the content regularly and consistently

Brain is also a muscle, the more regularly you use it on some topic with reputation, the better you become at it. Instead of studying once a week for a longer time, try to study in small slots of time regularly and review it over and over again, so that it will penetrate deeper in your brain.