These are the things you should do to feel more comfortable and nail your auditions!
1.Be Off-book
This should be obvious but BE OFF-BOOK at auditions. I know that it takes time and that you probably have other things in your life you have to do, but not having things memorized shows a lack of preparation.
2.Do Your Research
When you are going into an audition you should know the writers, director, and the original Broadway show (if it is a play or a musical.) If it's a TV show you should know the network and the vibe they want to exude.
3.Dress Appropriately
Remember to dress nicely, don't wear a costume but you should wear something that is in the same personality as the character. This usually goes for makeup and hair as well.
4.Be Confident
I know it's nerve racking to audition for anything, but being confident will help you in the long run.
5.Show Up Early
Another thing that I thought was obvious that a lot of people actually don't do. Outside of a car accident or something that dire, you should be on time if not early. Do whatever you have to do to be there because no matter what made you late, the casting directors are not going to care.
6.Make your Lines And Intentions Clear
Make your lines defined, and make sure that the character choices you make are structured and clear to an audience.
7.Hold the Sides
For anyone who doesn't know what sides are, they are written out lines you have to say. They're basically a sheet(s) of paper that have your lines/ monologue on them. Unless the audition you have prepared is very physical (has a lot of movement) you should hold your sides. Even if you are off-book you want to make sure you don't drop a line.
8.Make Smart Choices
Make smart choices in general, but especially with your character. Don't make a choice just to be remembered (for the wrong reason), but ones that make sense with your imagining or interpretation of the character.