how do I get closer to the metal?

Hello I am final year cs student. I consider myself an average programmer , but I think I can get better. The thing is I never feel I understand what's happening underneath all the abstraction. please tell me in which direction I need to go.
learn assembly
I know assembly but please recommend more books
learn c
I know c. (but we all know "know" is a relative term)
All recommendations are welcome. Please recommend resources.

I am final year cs student
Yet you don't know C or assembly? What the hell do they teach you in CS these days, Web apps?

Work your way down. Read Operating System Concepts (Jewish, but it it's a good book) and then the various O'Reilly books on the Linux kernel. Just learn how things work in a modern operating system. Then read something like The Art of Computer Programming.
If you want to learn about digital electronics (flip-flops, logic gates, etc.) then buy a breadboard and read Lessons in Electric Circuits (available for free online).