Method 2 - HOW TO HARMONIZE BACKGROUND VOCALS.
Method 2:
Step 1.
Listen to music as often as you can and stop singing along to the melodies. Hear what harmonies are sung on your favorite songs and practice singing only them. Part of learning background harmony is to develop an ear for it, or make it instinctive, so that you can sing harmonies to songs you have never even heard before.
Step 2.
Get together with another singer who knows harmony, preferably the person you will sing background to. Sing the melody of a song and let the other person show you one or both harmonies. Switch parts, and let the singer give you advice on how to be a stronger harmonizer. This, combined with practicing to every song you hear, is the most powerful way to learn harmony, especially if you do not play an instrument or even understand the theory of how you are harmonizing.
Step 3.
Play simple songs when practicing harmonies. In other words, play songs that have the same lead vocal structure and the same three or four chords throughout their duration.
Step 4.
Practice confidently and louder than you would when performing. When you are singing to a recording, you can really let loose and test your harmonies to see if they fit well and consistently with the song.