Singing loudly is very effective, but high-pitched songs are more effective. Many singers (Na Ying, Liu Huan, Han Hong. . As long as there is no tenor's mouth, even if it is a small Shenyang, Bao is not a small mouth.

Bel canto (Song Zu Ying, Zhang Ye. . ) You have a big mouth.

Then the Whispers (Faye Wong, Hannah Kim, etc.) kept silent and kept their mouths shut after singing for so many years.

If there is no good way, practice by yourself and often go to ktv.

Actually, I think small mouth looks good. Chun Wu and Daniel Wu Feng Ting have small mouths, which are charming.