What can knowledge be for you? When you consume knowledge, but do not translate it into life, it becomes shallow and useless. When you interpret knowledge, you attempt to make it yours and begin to feel to need to share it with others.
Deep knowledge is what changes your life and builds the world around you.
Shallow knowledge is what entertains your life and disregards the world around you.
The best way to deepen your knowledge is by being curious and critical. Do not accept every information people fed you, but challenge your comprehension. And when you can explain it to a child, you know how in-depth your knowledge is.