I have a sister that sings like an angel and im sitting here thinking that im the worst singer in the world.
Please help
Well, singing on key is really important. That just takes a lot of practice. Hum every day. Some pitch problems are from tense vocal chords though, and not a faulty ear. Sing do re mi type stuff. Do it slowly, and try to develop vibrato. Being able to sing with vibrato is a sign of being on the right track.
Try closing you mouth and hum a scale starting low. Towards the middle/higher notes, you should feel your nose, jaw, and/or bones right below your eyes somewhat vibrating. That is because the sound is projecting into your skull and that is important in having a loud clear voice that projects well. Over time, try to learn to sing that way.
Most importantly I think is to make sure that when you pronounce the words you sing, you are saying them just like you normally speak. Any unnatural position that your face, mouth, and throat go into while you sing is wrong, and you can’t improve until you get it to feel completely normal. Sure the mouth is important for pronouncing words, but the vocal chords are the only part of you that make any sound. It doesn’t require any muscles.