I. (adj., adv.) mikra, negranda;

(tiny) mikrega; tre mikra;
(small number or quantity) poka; nemulta.
a little - (adv.) kelke.
a little (of) - (some, indeterminate) kelka.
little by little - pokope; kelkope.
ever so little - preske nulo.
as little as possible - minim posible, minimo.

II. (n.) poko; kelko; kelketo.