What is a good way to learn how to sing harmony?

Answer 1

being able to sing harmony is all about understanding the relationship between 2 notes, so understanding a little music theory is good, and knowing the major and minor scales is pretty important too.

the major scale is the basic - do re mi fa so la ti do - pattern.
try doing thirds first, when someone sings "do" you sing "mi", when they sing "re" you sing "fa" and go from there. make sure you're singing the additional note, not just the same note that the other person is singing. or, record yourself singing the first part, and sing the second part over it. experiment with other relationships as well, try 4ths and 5ths and stuff just to see how they all sound.