How do you address friend that's your age in Spanish?

In Spanish, you typically address a friend of your age using the informal second-person pronoun "tú." You can greet them with phrases like "¿Cómo estás?" (How are you?) or simply use their name followed by "¿Qué tal?" (What's up?). For a more casual approach, you might also use colloquial terms of endearment or slang specific to your region.