Listen more and practice more
1. Practice scales loudly (1234567). Be sure to sing along with musical instruments with fixed pitch (such as piano, organ, harmonica, etc.), so as to cultivate intonation (this one should be practiced every day until you can sing accurately without the piano).
2. Sing along with the music. First, find some familiar songs to sing along with the music, and try to sing accurately (intonation). After practicing very well, sing the score with the music.
3. Pick up a new music score, listen to the music first, then sing the score without music, then listen to the music, compare where you are not good enough (mainly in intonation), and then correct it.
4. It is very important to cultivate your sense of rhythm when practicing (even if you sing accurately, you can't sing a tune well without rhythm).
After laying this foundation, you can try to listen to music notation. First, try to write down some familiar and short songs, and then check and correct your mistakes against the music. After practice, you can try to record some unfamiliar songs.
expanding materials
Listening training should pay more attention to step by step and use comparative methods.
For example, the comparison between chords and intervals within their own structures; Comparison of acoustic effects between the original form of interval and the transposed form; Comparison of sound effects of intervals and chords with the same nature and similar sound effects; The comparison between intervals and chords with different properties and large acoustic contrast. Practice can correct mistakes, and singing can take many forms.