what time is it?

One way which is common in Britain is to say the minutes first and then the hour. For minutes 1 to 30 we use past but for minutes 31 to 59 we use to.
Una forma molto comune in Inghilterra è quella di dire prima i minuti e poi l'ora. Per i minuti da 1 a 30 si usa "past", mentre per i minuti da 31-59, "to".

For example,

But...

instead of saying "15 minutes past", say (a) quarter past

instead of saying "15 minutes to", say (a) quarter to

instead of saying "30 minutes past", say half past

For example,

Another important rule is when the clock hands are on the hour we say o'clock in English.
Un'altra regola importante è che 'in punto' si dice "o'clock" in inglese.

For example:

12:00 (twelve o'clock)

13:00 (one o'clock)

Another way of telling the time which is more common in the USA which is easier for many people is to say the hour first and the minutes after, for example,
Un altro modo per dire l'ora, più comune negli USA e che risulta più semplice, sta nel dire prima l'ora e poi i minuti.

14:30 (two thirty)

18:26 (six twenty-six)

9:50 (nine fifty)

Remember that in the morning before 12:00 we always refer to the time as a.m. but after 12:00 we refer to the time as p.m.
Ricorda che di mattina, prima delle 12:00, usiamo "a.m.", mentre dopo le 12:00, "p.m.".