Learn to use the breath of "Dantian". If you use it, your voice will naturally light up and your throat will not feel very tired.
If you can't find it, you might as well do it according to my method and find some feelings.
1. Lie flat on the bed, put your hands on your waist and abdomen, and take a deep breath-feel the breath slowly flowing, and find the place where the breath stays, that is the abdomen, which is the power point of your singing. Remember that feeling.
2. Stand, arms akimbo, inhale-feel your waist slowly open, then remember this state, keep it when singing, and don't relax until the end of the song.
3. When singing high notes, pay attention to the sinking of the throat (but don't press the throat), and the breath should also sink, so that you can have enough strength to send the high notes up.
There is also: imitate the way dogs breathe (ha ~ ha ~ ha ~ ha ~), observe and learn, and you may find the feeling of breathing earlier.
When practicing, first lay a good foundation for the bass, and then slowly move towards the treble. Don't play high notes all the time, which is very harmful to your voice. Pay attention to excessive use of your voice.
For reference only. If in doubt, please consult again.