These very common words are frequently confused in everyday speech. Here is a helpful guide to help you avoid this confusion.
When we use 'a little' or 'little', the subject of our sentence should be singular, or an uncountable noun or collection of things indicated by a collective noun (which you treat as a singular word). Both are used to refer to a small quantity of something, but there is a subtle difference in meaning and usage between the two.
A little = some
Little = hardly any
As we can see, without the article (in this case 'a'), 'little' does not mean anything drastically different, but it tends to be used in a negative context. For example:
'A little' can also be used as a pronoun when your meaning is obvious from the context of the conversation.
'Little', on the other hand, is not common without a noun unless used in a more formal context.