While I can't speak on things like "musicality," or properly embodying your music, I know a lot about nerves!
For anything from a dance performance to a presentation at school, I get nervous like a mother cat! It's pretty bad... I have anxiety already, but those sorts of things ramp it up really far. I've had anxiety attacks over it!
So, here are some of my tips and things to keep in mind:
1) Remember that you WANT to do this! Say it to yourself in your head. Write it down. You WANT to. It's very important!
2) Breathe. Whether you're right behind the curtain, just before your actual performance, or just going to practice, or even just thinking about it at random (my worst time is just before I go to bed), remember to breathe deeply, into your belly. If you sing, or have done, it's a lot like that! This has been proven to reduce anxiety... and I certainly see the improvement, within moments. It'll also help teach your mind that you don't have to be so scared of it.
3) You're not nervous... you're Excited! One trick that came from Rosie Bitts, who taught me burlesque dancing. I was surprised to find it actually did help! Keep saying it to yourself, telling other people, etc. You might actually discover that you ARE excited to do it!
4) Remember that you are your worst critic... and that they usually aren't paying as close attention to you as you are. You may THINK that they will all see the flaws, the lack of something or presence of something else... but that is likely not true. I've been pole dancing for some time now, and every time I see a video of a dancer, unless I'm being intentionally critical (like someone needs help with a move), I generally just sit back and enjoy. Even when people ask me to look and be critical, I have a difficult time picking up everything I potentially could.
5) Eat. Seriously, eat food. Without food, you are much more prone to nervousness and added stress. When you feel healthy and full of food, you will be much more content, and much less apt to stress. Eat something before your performance, eat throughout the day, just keep doing it. Doesn't matter what kind of diet or whatever you're on: Hunger will not make you calm. Period.
Hope that helps!