Moving from books to implementations
In my opinion,

DSP is a tool. It is interesting in of itself but it is most interesting when used to solve real problems. 

Find an application, problem, or community that interests you. 

Take medical imaging as an example. Understanding the slice theorem is necessary but so is knowledge of anatomy and physiology. 

If something like RADAR interests you, knowledge of RF propagation is essential.

Do you like music? You can use DSP to like it more.

Look at other books beyond  signal processing. Think about how you could use DSP in your hobbies. 

Practicing DSP is about balancing function and constraints.