Etiquette advice tends to arrive as a long list of rules per country, most of which you forget by the second day. A smaller set of general habits does more work, because they signal attention rather than expertise.
Learn six words
Hello, please, thank you, sorry, yes, no. That is the entire vocabulary required to change how you are treated in most places. Nobody expects fluency. What people notice is that you tried before defaulting to English.
Volume and pace
Speaking volume varies enormously between cultures, and visitors are usually louder than the local norm in northern Europe and East Asia. Match the room. Similarly, in many countries a transaction begins with a greeting rather than a request, and skipping that step reads as rude even if your words are polite.

Dress
Religious sites almost universally require covered shoulders and knees, and many provide a wrap at the entrance. Outside sites, dress norms are looser but not absent. In smaller towns and conservative regions, beachwear away from the beach reads badly. Carrying a light scarf solves most of this.
Photography
Ask before photographing people, including street performers and market vendors. In some places a photograph is a paid transaction and that is a legitimate expectation, not a scam. Religious ceremonies and military installations are usually off limits, sometimes legally.

Tipping
Tipping norms are genuinely inconsistent and getting them wrong is not a moral failure. Look it up for your destination. Broad shape: substantial in the United States, modest rounding in most of Europe, and effectively absent or even unwelcome in Japan and South Korea.
Queuing, eating and personal space
- In some countries a queue is a strict line, in others it is a loose cluster, watch before joining
- Eating while walking is normal in some cities and impolite in others, including much of Japan
- Personal space distance varies by around half a metre between northern Europe and the Mediterranean
The general principle is simple enough: arrive slightly quieter and slightly more formal than you think is necessary, then adjust to what you observe. It is much easier to relax than to recover.
Read the regional chapter for your destination before you travel.
