Latin America is not homogenous across state borders when it comes to addressing each other: While Costa Ricans tend to gravitate toward the formal usted form of address among themselves, Nicaraguans prefer the friendly vos (second person) form with each other, although tú is widely understood.
For travelers, it’s best to use usted until you’ve really gotten to know someone (or mastered the tricky vos form), particularly after a night out or a long drinking session (you’ll be surprised how quickly alcohol lubricates friendships at this latitude).
The term don for men and doña for women is a colonial term of respect usually related to aristocracy or landownership, but in Nicaragua  it’s far more commonly used than elsewhere in Latin America, and indicates a higher level of respect or affection, particularly for the elderly, the important, or the wealthy.
Practitioners of certain careers sometimes drop their names entirely and go by their profession. That is, it’s not uncommon to be presented to someone everyone calls simply “la doctora,” “el ingeniero,” or “la abogada.” Just go with it and smile.
It’s customary to kiss women on the cheek when greeting, but women will provide the signal whether that’s appropriate or not by turning their cheek toward you. Men will offer you their hands for a stiff handshake. When someone new enters the room, rise from your seat to greet them, and when you’re ready to end a conversation or leave the room, a friendly “con permiso” will pave the way to the door.