Read other people's code. Write code that will be reviewed by other people. Review other people's code. Do this with many different projects/sets of people. Goi

Read other people's code. Write code that will be reviewed by other people. Review other people's code. Do this with many different projects/sets of people. Going for something like GObject to Linux Kernel codebases (both in C) is like going from the Earth to Mars. You will learn something. Now if you want to strengthen your Computer Science skills, I suggest taking formal Computer Science courses. I think some US universities have classes available on the web. The math part is very important. Or you could start by reading something like Introduction to Algorithms from Thomas H. Cormen. Or the book from Sedgewick.