Mix up the skills

What do I mean by 'mixing up the skills'?

Simply to do two or more of reading, listening, writing, and speaking at once. You could also throw other skills in there--sing, summarize, draw . . . the sky's the limit.

Why do I say that?

Because the brain becomes stimulated when you use many of its areas simultaneously. And then it learns better. Think of it as the beauty of multi-tasking. 

If I read and listen to the same text in German, I understand more of the language than if I did either alone. There's stuff I recognize listening that I wouldn't just by reading. There's stuff I recognize listening that I wouldn't just by listening.

Using Venn diagrams it's A union B. (Not their intersection).