FEW/LITTLE WITH A NOUN

We use FEW for plural nouns and  LITTLE for singular nouns (usually uncountable) to talk about a small number or quantity of something.

We've got a little milk and a few eggs
Few politicians are really honest
There were few people at the meeting
Just a little wine, please
Can I try a little of that, please?

FEW/LITTLE WITHOUT A NOUN

If the noun has already been mentioned, we can just drop it and use FEW or LITTLE alone
 
- Some more soup?   - Just a little, please
- How many people were there?   - Few 

A LITTLE + adjectives / adverbs

We can use A LITTLE to modify adjectives and adverbs (answering the question HOW):

- I'm a little tired today
- Trains here go a little too slow
- I just met you but I already love you a little

Few or a Few / Little or a little?

FEW and LITTLE can use the article A. See the difference:
 
- I've got few friends here, I need to meet knew people   (negative idea: I need more)
- I've got a few friends here, so we can go out with them  (positive idea: it's enough)
 
- There's little food, we can't survive here for a week  (negative)
- Great! There's a little food here. I'm so hungry!  (positive)
 
Note: FEW and LITTLE, with no article, are very formal. In an informal style we prefer to say NOT MUCH/MANY.
 
- We've got little time (formal) = We haven't got much time (informal)
- Few people understand quantum physics = Not many people understand quantum physics

A BIT (colloquial)

In colloquial English we very often use A BIT OF + noun and A BIT + adjective instead of A LITTLE

- I only had a bit of wine = I only had a little wine
- It's a bit noisy here = It's a little noisy here