Adverbs (avverbi) are used to clarify or modify other parts of speech. There are many different kinds of adverbs.

Derivative Adverbs

Avverbi derivati are adverbs derived from adjectives. Usually a suffix -mente needs to be added to form them:

felice (adjective meaning happy) - felicemente (adverb meaning happily)

The adjectives from which adverbs are derived are often in their feminine form:

vera (feminine adjective meaning true) - veramente (adverb meaning truly)
sincera (feminine adjective meaning sincere) - sinceramente (adverb meaning sincerely)

In case of adjectives ending in -re or -le the last letter, “e”, has to be dropped before the suffix -mente can be added:

generale (adverb meaning general) - generalmente (adjective meaning generally)
gentile (adjective meaning polite) - gentilmente (adverb meaning politely)

Adverbs of time

Adverbs of time (avverbi di tempo) refer to time frame or frequency. Some derivative adverbs are also adverbs of time e.g. frequentemente (frequently), raramente (rarely). Other important adverbs of time include:

Ora, adesso - now
Poi - later
Ieri - yesterday
Oggi - today
Domani - tomorrow
Dopo - after
Già - already
Mai - never
Ogni giorno - every day
Sempre - always
Stasera - tonight

In some grammar resources adverbs of time and adverbs of frequency are treated as separate categories.

Adverbs of Place

Adverbs of place (avverbi di luogo) are used to describe a location. Some often used adverbs of place include:

Qui/Qua - here
Vicino - close
Lontano - Far
Ovunque, dappertutto - everywhere
A sinistra - left of
A destra - right of

Adverbs of Manner

Adverbs of manner (avverbi di modo) describe a way in which an action is performed. A lot of adverbs of manner are also derivative adverbs so the same rules of formation apply

tranquilla (feminine adjective meaning calm) - tranquillamente (adverb meaning calmly)
veloce (adjective meaning fast) - velocemente (adverb meaning rapidly)

Other important adverbs of manner include the following:

molto - very
insieme - together
da solo - on one’s own
con fatica - with difficulty
quasi - almost