Hi!
I understand your doubts! It's very complicated for us not to use articles when we're learning English as well :)
I can't promise to be exhaustive, but these are the most common cases I can think of:
- When the object you're talking about is definite, especially if it's already been named before (the most obvious case). "Have you seen the movie?" = "Hai visto il film?" because we both know what film you're talking about!
- When you're talking about general concepts, like moral values, feelings... you always use the article. I think this is the main difference between English and Italian! In general, try to use it whenever your case is similar to these:
"Love is blind" = "L'amore è cieco"; "Freedom is important" = "La libertà è importante"; "Life is a gift" = "La vita è un dono"
- With possessive adjectives and pronouns.
"My book" = "Il mio libro", "His friends" = "I suoi amici".... "His book is new, mine isn't" = "Il suo libro è nuovo, il mio no".
Exception: names of relatives: "My dad" = "mio padre" (NOT "il mio padre")!
- When talking about geographical destinations such as countries or regions, seas, lakes or mountains (not cities):
"Il Po" (river), "La Germania" (Germany) (though you don't use it when they're : "Sono stato in vacanza in Germania quest'estate").
There are more complicated circumstances but you can't learn them all at once! You'll get used to it listening! :)
I hope this is useful.
Francesca