I'm a big fan of rubber duck debugging, which is essentially getting an inanimate object and explaining how your code works, step by step. It makes you feel weird, and people will think you're losing your mind, but if you don't care about those things then it's actually very helpful. I've solved many a problem talking to a stuffed animal 😂

Slow and methodical. Just think, consider the errors being spit out and try to narrow down where the error could be coming from. console.log is your friend.

It's tricky question, but for debugging approach I recommend you to use any kind of linter and code intelisense which help you a lot and make your process way smoother.