Adverbs modify verbs. If you’re using an adverb to modify a verb, then ask yourself why you need to. Is the verb not doing its job? If the verb alone can’t tell your reader how someone or something is doing something without an adverb, then is it the right one to use?
John walked quickly down the street.
You want your reader to know how John walked, so if he’s walking quickly, then say so – right? Well, no.
John hurried down the street.
One word instead of two – hurried – tells us exactly how John is moving.