You get proficient at C programming by properly understanding what you learn rather than spend countless hours in trial and error cycles.
There isn't much magic to it and the concepts are quite simple. In my opinion if you're looking to get up to speed quickly instead of carefully writing code then C is not for you.
In your opinion, what would be:
1. the modern equivalent of K&R?
2. a solid reference to keep around and consult afterwards?
(with 1 and only 1 answer to the questions above, please, not a list, 'cause every time I search "learn c" I get over lists upon lists, of high quality comments - which is bad because you can't actually dismiss them as rubish, you actually have to read them -, that only throw you into paralysis by analysis, so you just say, "fuck it, just grab K&R or LCTHW, then grab a C open source project you feel like hacking on and start banging you head on it"...)
2. The C standard draft, your compiler(s') manual and man pages if you're on POSIX. Also pencil and paper for drawing your arrays.
Clarification about 1: Haskell has good solutions to a lot of problems that have plagued programming, learn them because they are not language-specific but are mindset-specific. The advantage is that once your mindset changes, you start paying attention to off-by-one errors and potential overflows and overruns. You also start paying attention to using the correct types in a C program and you start taking advantage of enums to reduce the space of possible states in each function in your program. Once this clicks, memory management is a breeze.
Also learn the mindset of solving the problem at hand and nothing but the problem at hand. C is not a language for creating abstractions everywhere, it's a language for writing down as little steps as possible to solve that specific problem.