Article in English: A good teacher can give you detailed feedback and advice on how to improve your voice. Aim for someone with classical training, as a classically-trained teacher is likely to have experience with a variety of styles. Listen to the way they handle their breath, volume, articulation, control, vocal habits, and resonance. If you’re particularly fond of their style, see if you can replicate it. Replicating someone’s style is a great way of learning to sing, because it forces you to try things you might not normally try when singing. Pay attention to how they breathe and support the notes with their breath. Note their posture and body language. Watch the way they use their lips to shape the sounds and words that they are singing. Think about why you dislike a certain singer or speaker. What do they do differently from the ones you like? Are they doing something wrong or is it just not your style? It is amazing what a good sound engineer can accomplish during a recording session. If you really like an artist's recordings, try to figure out how much is real and how much is engineered before you decide that "you can never sound as good as that!" Ask those whose voice you like what they are doing to get that sound. Most will be flattered and pleased to share this information with you.

Summary in Vietnamese:
Tìm thầy có chuyên môn giỏi. Lắng nghe thật kỹ giọng của các ca sĩ và diễn giả chuyên nghiệp. Xem các ca sĩ và diễn giả chuyên nghiệp trình diễn. Đừng bỏ qua những người chuyên nghiệp mà bạn không thích. So sánh giọng của một ca sĩ khi họ hát trực tiếp và trong bản thu âm của họ. Đến các buổi trình diễn của những ca sĩ không chuyên và các sự kiện âm nhạc khác ở địa phương.