How can I contribute to open-source while learning CS?

[mahesh]

I am teaching myself CS and in a couple or more months (though also basically now) I'd be searching for open-source projects to apply some programming skills (Python, C/C++ at least). I'd like to start with minor fixes or improvements to non-OS programs like Audacious or pdf readers etc.
Is it possible to implement that? If yes, then what's the routine?