Sometimes I get confused on when I should be using an adverb or an adjective. What's a good rule set?
For example, one can respond to a question with "bona" or "bone" - but when do I use which?
Adjectives describe nouns; that's basically all they do. So if there isn't a noun or pronoun to modify, you use the adverb form.
Note that adjectives can describe nouns through linking verbs:
Note the two different meanings!
It is more common to use Bone by default. You can say Bona if you are referring to a noun. Example, your friend bought a new videogame and you say Bona because you like the game. However, Bone would work in that situation as well.