Adverbs are words that qualify verbs, adjectives or other adverbs,

e.g. He ate quickly; She is quite tall; She is amazingly happy


Most adverbs in English are formed by adding -ly to an adjective.   In Spanish, you add -mente to the feminine form of the adjective,

e.g. rápido - quick > rápidamente - quickly; fácil - easy > fácilmente - easily


When you have two adverbs ending in -mente together in a sentence, remove the -mente from the first adverb,

e.g. Lo hizo rápida y fácilmente - He did it quickly and easily.


Here are a list of common adverbs which don't end in -mente.   You just have to learn them as items of vocabulary!

ahora now casi almost nunca never
algunas veces sometimes demasiado too poco a little
allí there deprisa quickly tan so
aquí here despacio slowly tarde late
a menudo often mal badly todavía still
a veces sometimes muchas veces a lot siempre always
bastante quite mucho a lot of solamente only
bien well muy very ya already