One is for things you can count, the other is for things you cannot count.
"Few" is used with countable nouns: there are not many units of something. "Few people came" = not many people came. Without an article, it has a negative nuance.
I have a few friends in this city.
Only a few students passed the exam.
She speaks few languages fluently.
"Little" is used with uncountable nouns: there is not much of something. "Little time remains" = not much time is left. Without an article, it also has a negative nuance.
There is very little time left.
She put a little sugar in her coffee.
He has little patience for excuses.
Common mistake
Trick to remember it
Quick rule
Did you know?
"A few" and "a little" (with the article) are positive or neutral: "I have a few friends" = some friends, fine. "I have a little time" = some time, manageable. Without the article, "few" and "little" are negative or pessimistic: "I have few friends" = almost no friends (implies loneliness). "I have little time" = very little time (implies pressure). The article "a" transforms the connotation entirely, just as in the few/a few pair you already know.
Exercise 1 · Pick the right one
There is very _____ sugar left. We need to buy more.
Exercise 2 · Pick the right one
Very _____ students passed the exam. Most of the class failed.
Exercise 3 · Form the word
One reduces uncountable things, the other reduces countable things.
'A' is used before consonant sounds; 'an' is used before vowel sounds.
'A lot of' works for countable and uncountable; 'many' only for countable; 'much' only for uncountable.
'According to' cites an external source; 'based on' indicates the evidence behind a claim.
Bryan López
Founder of SpeakUP Academy