Been on YouTube for nearly 20 years. The number one rule if you want subscribers, you have to tell people to subscribe. Like, after you release an album on DistroKid, when it goes live you could release a single track video on your channel and put in the video to Subscribe, Hit the Bell, leave a comment and like your videos. Also advertise when your uploading schedule is on your next album. Give people a reason to come back. Also, place it in your bio as well.