Join a good choir. Chances are, it will be led by a good director, and will sing challenging music. Let go of your ego, and do everything your choir director tells you to do, to the letter. Endeavor to be the best chorister you possibly can be- learn to read music, to sight-read, to blend your voice with others in your section, to listen to how your section and your own voice harmonize with the other sections and other voices, pay attention to dynamics, appreciate the music you are singing, train your voice to the best of your ability based on the resources you have, take voice lessons if you have the time and money, There- THAT'S everything the two above posters suggested, rolled up in a neat package and delivered, special delivery, to you- your active listening, your note space, your dynamics, your spectral balances, your things that make you forget that it's just a recording ('cause it ain't, it real,) your experience, your a whole lot of listening.