I was initially hesitant about getting too close to my subjects, afraid of invading their privacy. But I've found over the years that most people like to have their pictures taken - if they feel they are being admired, respected, and treated like a person, not a trophy. Before I travel, I always try to learn as much as I can about the customs, mores and even gestures of the host country. A few words or phrases in the local language are always appreciated and can really help to open doors. In a small monastery in Maymyo, Myanmar, I lined up five young monks in the light and bounced the light from a small gold reflector into their faces.
All photographers have their own style.
Some are pushy, some silent and some are flamboyant and loud. All kinds of approaches work. I prefer a direct, personable exchange. No matter what your style is, you need to make it clear to the person what you want to shoot - an over all shot or just their face, hands or dress. And then you need to make sure you fill the frame with only that.