(A) a little/little (adjectives) are used before uncountable nouns:
a little salt/little salt
a few/few (adjectives) are used before plural nouns:
a few people/few people
All four can also be used as pronouns, either alone or with of:
Sugar? — A little, please.
Only a few of these are any good.
(B) a little, a few (adjectives and pronouns)
a little is a small amount, or what the speaker considers a small amount. a few is a small number, or what the speaker consider a small number.
only placed before a little/a few emphasizes that the number or amount really is small in the speaker’s opinion:
Only a few of our customers have accounts.
But quite placed before a few increases the number considerably:
I have quite a few books on art. ( quite a lot of books)
(C) Little and few (adjectives and pronouns)
Little and few denote scarcity or lack and have almost the force of a negative:
There was little time for consultation.
Little is known about the side – effects of this drug.
Few towns have such spplendid trees.
This use of little and few is mainly confined to written English (probably because in conversation little and few might easily be mistaken for a little/a few). In conversation, therefore, little and few are normally replaced by hardly any. A negative verb + much/many is also possible:
We saw little = We saw hardly anything/We didn’t see much.
Tourists come here but hardly but few stay overnight = Tourists come here but hardly any stay overnight.
But little and few can be used more freely when they are qualified by so, very, too, extremely, comparatively, relatively etc.
fewer (comparative) can also be used more freely.
I’m unwilling to try a drug I know so little about.
They have too many technicians, we have too few.
There are fewer butterflies every year.
(D) a little/little (adverbs)
(1) a little can be used:
(a) with verbs: It rained a little during the night.
They grumbled a little about having to wait.
(b) with ‘unfavourable’ adjectives and adverbs:
a little anxious a little unwillingly
a little annoyed a little impatiently
(c) with comparative adjectives or adverbs:
The paper should be a little thicker.
Can’t you walk a little faster?
rather could replace a little in (b) and can also be used before comparatives, though a little is more usual.
In colloquial English a bit could be used instead of a little in all the above examples.
(2) little is used chiefly with better or more in fairly formal style:
His second suggestion was little (= not much) better than his first.
He was little (= not much) more than a child when his father died.
It can also, in formal English, be placed before certain verbs, for example expect, know, suspect, think:
He little expected to find himself in prison.
He little thought that one day. . . . . .
Note also the adjectives little-known and little-used:
a little-known painter a little-used foothpath