Let the patient guide you
Searching for a diagnosis is like trying to find a certain room in a large building complex. The quickest and easiest way is to ask the person who knows where the rooms are and who has the keys to all the rooms.
This person is the patient.
Ask them where to go, and let them lead you. Don’t try and jump ahead, just follow them to the correct destination. If you start jumping, and thinking ‘I think this is pneumonia’, you’re essentially running ahead to a random room and asking ‘is it in here?’. Wait till the patient has told you everything, and see where you’ve ended up.