I can't think of much related to C code specifically. C code has it's pitfalls for sure, but with discipline (a lot of discipline) most can be avoided. There are tools. Find out about them. Try them. Learn about what they can do for you. Use them as part of your builds.
Don't rely on tools because even with these tools, the best way is finding out the other things the tools can't catch -- and these are not at all obvious. I was just thinking of some of Daniel J. Bernstein's code and even the few flaws found in it. It also shows how hard it is to be sure of the correctness of any length of program without trying to run it.
Read.
What is it that is not working?
What do you need?
Ask: What needs to be done?
Keep It Simple Smart (KISS)
Learn what not to do.
There are no ready answers.