Avoid RFCs unless you're working on a specific problem. You're also not going to be able to become an expert in all the different fields, so focus on specific fields.

For IP networking, I can specific recommend the following books as "force multipliers" of knowledge:

- Routing TCP/IP (Cisco Press)

- Network Warrior (O'Reilly, Cisco-centric, but good, easy to digest intermediate knowledge of layer 2 and 3)

- TCP/Illustrated (A deep dive into TCP/IP. RFC-level depth but easier to conceptualize)

If you're looking for recommendations for other specific areas, let me know and I can probably point you in the right direction.