What etiquette mistakes should first-time visitors avoid in Japan?
You do not need to perform Japan perfectly. Be quiet where others are quiet, queue properly, handle rubbish and shoes thoughtfully, and watch what locals do before making yourself the loudest person in the room.
Answer
Japan etiquette advice can become theatrical online, as if every meal is a test and every train ride has secret rules. The useful version is simpler. Keep your voice down on public transport, queue properly, respect shoes-off spaces, avoid blocking narrow streets or station gates, and be thoughtful with rubbish, baths and temple or shrine behaviour. Restaurants may have their own rhythm; watch before barging in. You will make small mistakes, and most travellers do. What matters is not flawless performance, but noticing the setting and adjusting. Courtesy goes further than memorising a dozen brittle rules.