spanish and italian: So THESE words are feminine and THESE words are masculine, and you ALWAYS put an adjective AFTER the noun.
Not quite true, actually. At least in Spanish, it's often correct to use either adjective-noun or noun-adjective. In most cases, noun-adjective sounds more natural, and is what you'd typically use in spoken language, unless you're going for a particular effect. It also depends on the specific function the adjective in the sentence and probably some other stuff as well.
I don't remember enough Italian to say, but I seem to recall something similar.
From what I understand from my Spanish studies so far, an adjective that modifies the noun goes after it, while an adjective that is an inherent part of the noun, so to speak, goes before it. Is that accurate? :-/
Something like that. Adjective position can shift emphasis from marking a distinction between one thing that has one quality and one that doesn't, versus saying that a quality that a thing has is an important part of it (adjective last vs adjective first, respectively). Sometimes, anyway, depending.
Figuring out any comprehensive rules for this is hard. And it varies by dialect, too, for example rioplatense (what I speak) uses less adjective first than neutral. So yeah.