"a little" is positive, whereas "little" is negative. For instance, if I say, "I have a little money," it means that I have enough, whereas, "I have little money," means that I am poor. Similarly with "few" and "a few". If I say, "I have a few friends," it means that I have enough. However, "I have few friends," means that I don't have many friends. You could regard "a little" and "a few" as meaning "some".