Store jewelry in it's original packaging or a jewelry box that seals out light, dust particles, and moisture. Brass naturally develops a patina, which over the course of time adds dimension, character, and beauty with age.
An easy way to get the look is to avoid polishing and let oxygen & your natural body chemistry create a 'living' finish. Polish from time to time if you'd like to maintain the original shine & brightness.
Brass polishing cloths are available for purchase here: Brass Cleaning Cloth