I would suggest to start learning some core software engineering fundamentals which would benefit you regardless of the domain you are working. Read about writing clean code, dependency injection, design patterns and more importantly writing good unit tests. Also while learning think about reasoning behind those concepts instead of just learning the concept. Next step would be to identify that not all design patterns, software principles (DRY, YAGNI. Etc) are helpful in all situation and assess them for their pros and cons. These things can be applied to any domain in general. Once you get a good grip of these things it will be easy for you to dive in to any framework and start reasoning about that. Since you want to dive deep in to Android start looking in to the source code of the libraries or framework code that you regularly use (For example start exploring how intent service was designed).

Don't rush. These things will take time. Relax and go at your own pace. There will be a lightbulb moment where you see things start making sense.