Practice breathing is divided into two stages, first improve the vital capacity, and then practice breathing control.

Aerobic exercise can improve vital capacity, so can deep breathing yoga.

I have used a very effective method and recommend it to you: spread a napkin on the wall and blow it evenly with your mouth, so that it won't fall on the wall, and the longer you stay, the better.

Different styles of songs have different requirements for breath control and cannot be generalized.