How do I return a greeting?

Excuse me, could you possibly elaborate on the proper etiquette for returning a greeting? I've noticed that there seems to be a variety of approaches depending on the situation and culture, and I'd like to ensure that I'm responding appropriately and respectfully. Is it sufficient to simply mirror the greeting I receive, or are there specific phrases or gestures that are more appropriate in certain contexts? Additionally, I'm curious about the nuances of nonverbal communication, such as eye contact and facial expressions, that may influence how a greeting is perceived. Could you please provide some guidance on how to navigate these various aspects of returning a greeting in a polite and considerate manner?