Hey Camille!

Long time no see(or chat. lol!). I'm currently working on a song called "Giants in the Sky". I'm pretty proficient at it, except for the second verse. The piano instrumental doesn't benefit the voice exactly that well in that part, and I find myself getting off-tune. I can sing the pitches perfectly acapella in that part. However, I just can't do it with the instrumental. I feel like it is complementary to my struggle of learning to harmonize.

Do you have any tips?

Great song! Sondheim is notoriously tricky; great practice, though!

I recommend uploading a version with vocals & accompaniment to https://vocalremover.org/ and turning down the volume of the lead vocal bit by bit. That way, you're easing yourself into singing without a guide!