Cultural sensitivity is so important, wherever you might be in the world. It’s essential you respect the people in the country you are visiting, and that you remember how to behave. It will show that you have done your research and you know how to conduct yourself.
It is especially important to respect the religion of the country you are visiting. Dress modestly and always cover your knees and shoulders in a place of worship. You should be mindful of this if you are visiting a Muslim country, like Indonesia or Malaysia. You won’t be expected to cover up entirely, but dress respectfully and make sure you limit beachwear to the beach, where it is mostly tourists.
Find out if the country has a king or queen, and look into the political situation. Avoid conversations about religion or about the royal family in case it is perceived you are being negative about them.