Italian adjectives usually come after the noun. Their position is lax, however, and often this rule is set aside for poetic purposes or for more clarity.
When there is a collocation in use, the adjective is in its most common position:
Bel tempo. (nice weather)
Cielo azzurro. (blue sky)
The usage of tempo bello or azzurro cielo is permitted, due to the lax way Italian handles the elements in a sentence, but such forms sound unconventional, old-fashioned and may be much more likely found in poetry than in an everyday conversation (during which they would sound weird). Because of this, they can can come before a noun for emphasis, too. When the adjective covers an uncommon position, it stands out.
Buona cena can be included in this category: buona cena is much more common than cena buona, so you would use Questa è stata una buona cena. The same applies to buona donna (although, donna buona would be perfect as well).
The superlative works differently here, in that both forms sound natural. Buonissima cena is not a collocation, so the ear is not "trained" on a specific order of the sentence.
Now for a more subtle feature:
A few adjectives (very few!) change the meaning on a sentence depending on their position. These are basic adjectives such as alto, basso, vecchio, nuovo.
Un vecchio amico. Un amico vecchio.
You would translate both as an old friend. The first one translates an old friend, meaning someone you've known for years. The sentence where the adjective comes after the noun, however, means that this certain friend is old.
Un alto ufficiale. Un ufficiale alto.
A high (tall) official. (meaning, an important official). A tall official. (meaning, a 6 ft official!)
Ho comprato una nuova casa. Ho comprato una casa nuova.
"I bought a new home".
The first one translates so. The first one implies that you had a house and bought a new one. The second sentence, however, doesn't, because it tells that you bought a house that was newly built, and it could be your first.
Luckily there are not many adjectives that behave this way, but their use is erratic and can only be learnt with practice.
Hope this helps!