I've found it very helpful to rubber duck comments to get into the right why mode. Consider how you'd explain this piece of code to a less experienced guy on th

I've found it very helpful to rubber duck comments to get into the right why mode. Consider how you'd explain this piece of code to a less experienced guy on the team - and write down exactly that. Why was this added? Why was the old thing in place changed, what broke and had to be changed? Why didn't you do the other obvious thing? And remember - usually you should explain something until it's clear for you, and then one more step.