Oh, gosh.
Solos.
I sing in a large choir that tours internationally. I've gotten several solos, and the longest (thirty measures) was a capella. They are so scary!!! I have this talent for not singing on pitch when I'm nervous, and this could've led me down some not-so-good roads. Here's what I've learned:
For singing on pitch:
** This takes a lot of determination, and you have to support your lower abs and breathe deeply. If you don't breathe deep enough, (think of the air as falling deep into your body, all the way down to your toes), then your pitch will be flat. But if you have too much air, your tone will go sharp.
** You also have to care about your pitch. I know this sounds like it doesn't work, but believe me, it does. If you think your pitch right before you begin to sing, your voice will come out in tune. Listen for the other parts or the accompaniment and you can find your pitch.
For not being nervous:
**There's really not an exact formula for this. Nervous is not necessarily a bad thing, but it does make you feel extremely uncomfortable and jittery. I always get really freaked out right before a solo, and my mouth dries up. But once I start singing, that all fades away and I'm fine.
**If you really don't like feeling nervous, just think about how good you'll feel once things are all over, and how good a job you'll do. Concentrate on the ending of your solo, and don't worry too much. If you practice enough and you know your part, you'll do fine.
Also, facial expression is everything. Make sure to communicate to your audience the tone and meaning of the song; don't keep your face expressionless and your words meaningless. Really feel the lyrics, and don't be afraid to move your head or sway your body. The audience will love to see how involved you feel with the music, and, believe it or not, your facial expression will enhance your tone.
Good luck! I'm sure you'll do amazing.