Colleges don’t talk about program performance; I find this strange since they focus so much on student performance!
Develop the habit of instrumenting your code by default — figure out the correct timer to use for your platform, and measure, measure, measure. Understand the interplay between the code you write, what the compiler does to it, and how it runs on the CPU.
Investigate the tools available on your platform, and experiment with these. You will learn a lot from this than you can ever imagine!