That's much easier said than done. I know. For years it mystified me why I could perform on a stage in front of hundreds of people and not get nervous, but I'd crash and burn due to nerves during auditions and juries. I chalked it up to "the pressure." It took me years to realize that "the pressure" was largely composed of my focus on my vocal deficiencies and trying to control and fix those rather than focusing on my strengths. Yes, of course in an audition you're singing for someone who will notice your mistakes--they're not sitting there wanting to be entertained and they are there to compare you to others. But you don't have to compare yourself to others. This was one of the big differences for me between performing and auditioning--in a performance I wasn't busy comparing and measuring myself against others. Additionally, you have no control over what you haven't learned to do well yet. And most of the time you don't know what a director is looking for and you can't really control that. So why not go into an audition saying to yourself "You know what, I do this one thing really well, and if I show them that I can do this one thing really well in this audition, I'll consider that a success." I used to think that the key was just focusing on one thing at a time and I used to say to myself "Here's this one thing I really struggle with. In fact I've been struggling with it year after year and I kind of feel like I'm banging my head against a brick wall, but if I just manage to that well in this audition then I'll be happy with my performance." I also used to think that the whimpy non-progressing way to learn was to focus on the things I felt comfortable doing and thought I did well. So i didn't. I tried to tackle everything I thought was wrong with my voice. I have learned that you actually make more progress when you're kind to yourself. Focusing on your strengths and the positive doesn't mean that you won't try to learn new things. It means that you're a lot less likely to get hopelessly discouraged.
Vocal self-consciousness pervades our society. People try to "fix" their speaking voices and their singing voices--or they simply avoid speaking and singing. But learning to sing isn't really about fixing anything. It's about molding and shaping what you have. I'm always a little sad when I look around my church and notice how many people aren't singing. People often tell me that they "can't" sing. In most cases, this is simply untrue. Maybe you don't know if you're singing in tune or not, maybe you know you can't hit high notes, but neither of those means you can't sing. I wish that more people gave themselves permission to sing imperfectly because I'm afraid that all of us are getting too little exposure to real unfiltered human sound. I know moms who won't with to/with their kids. that's just heartbreaking to me. You can't sing in tune? That's okay. You think your voice is scratchy or screechy? That's okay. Too quite? Fine. Breathy, wispy, shaky? All okay. I mean, if you want to you could learn to fix those things, but there is inherent beauty in human vocalization, and I for one, want to hear more of it.