I think the Feynman Method is equally applicable to debugging; I've also done some teaching before, and seen far too many beginners open the debugger at the first bug they find and start stepping aimlessly through the code, seemingly unaware of what their code should be doing. They eventually reach the point where the program outputs the wrong result, and have no better understanding of what they did wrong, because they were too focused on what the code is doing to think about what it should be doing. I call it "debugger-induced tunnel vision".

My advice on this is to, before even thinking about using a debugger, think carefully about and write down if necessary the conditions and values expected at certain points in the code. Then, and only then, should you use the debugger to confirm or deny those hypotheses. In practice, with those I've taught, guiding them through this procedure, they often realise the source of the bug before using the debugger.