Adjective placement (Adv.)
Introduction
You were most likely taught that in Spanish, adjectives almost always follow their nouns. And this is a good rule of thumb, especially when you are just starting out with Spanish and need a few concrete rules to eliminate confusion. But there are many situations in which adjectives do not necessarily need to follow their nouns, and in which having the adjective precede the noun is actually better Spanish.
Restrictive and non-restrictive adjectives
So how do you know which adjectives should go where? In general, restrictive adjectives must follow nouns, while non-restrictive adjectives can either precede or follow nouns. Many set phrases and expressions require that adjectives be pre-posed (placed before the noun).
This raises a different question with a more complicated answer. What are restrictive and non-restrictive adjectives, and how do you tell which is which? A restrictive adjective is one that limits the meaning of the noun it describes -- "restricting" it in some way. Take an English example: "The purple flowers are my favorite." The adjective "purple" places a restriction on "flowers" by designating only a specific color. In Spanish, therefore, we would place the adjective after the noun: Las flores moradas son mis favoritas. Non-restrictive adjectives, on the other hand, do not limit the meaning of their nouns. So we may have something like "the beautiful streets of the town," translating to las bellas calles del pueblo where the implication is that all of the streets are beautiful. No streets are excluded by this statement. On the other hand, the translation las calles hermosas del pueblo gives the subtle implication that some streets are beautiful, and others not.
Restrictive adjectives must follow their nouns; non-restrictive adjectives may precede or follow nouns.