Formal (but friendly):
* "Hola, ¿cómo estás?" (Hello, how are you?) - This is a polite and common greeting, but a bit more formal than the options below.
* "Buenos días/tardes/noches" (Good morning/afternoon/evening) - This is a more formal greeting, suitable for all times of day.
Informal (common among friends):
* "¿Qué tal?" (How's it going?) - This is a casual and common greeting among friends.
* "¿Cómo andas?" (How are you doing?) - Similar to "¿Qué tal?", this is another informal greeting.
* "Qué onda" (What's up?) - This is a very informal greeting, commonly used among young people and close friends.
* "Hey, ¿cómo estás?" - This is a more casual variation of "Hola, ¿cómo estás?".
More affectionate (if they're very close):
* "Hermano/Amigo, ¿qué pasa?" (Brother/Friend, what's up?) - This is a very informal and affectionate greeting, used between close friends.
* "Cabrón/Amigo, ¿cómo estás?" (Dude/Friend, how are you?) - This is an extremely informal and playful greeting, only used between very close friends. It can be considered vulgar in some contexts.
Other greetings:
* "Un abrazo, amigo" (A hug, friend) - This is a common greeting between close friends, often accompanied by an actual hug.
* "Qué gusto verte" (It's nice to see you) - This is a very friendly greeting.
* "Cuánto tiempo" (Long time no see) - This is a way of acknowledging that it's been a while since they last saw each other.
The best way to greet someone depends on the context, the age of the people involved, and the level of their relationship. If you're unsure about the proper greeting, it's always best to err on the side of formality.