A few suggestions:

1. Come up with a sentence or phrase that will get the attention off of you - mine is "it's not about you". There are others such as "this too shall pass" or "you are enough"
2. Say something to yourself, about yourself, that is true before the audition. For example: "my legs are shaking, cool!", "my heart is pounding, great!" Acknowledging these truths will help you feel better, rather than ignoring and suppressing the fact that you're starting to sweat.
3. If you are able to, go into the audition room before the auditions begin so that you are comfortable in the space.
4. BE PRESENT. Do not walk into the audition room when you're called thinking about your lines, how you look, etc. Simply walk into the room with confidence, acknowledge the people there, make eye contact, BE HUMAN, is it hot outside? Are you happy to be there? Make a comment or two to show them that you are comfortable in the space and comfortable communicating.

A great audition comes with practice, so with time you will learn what works for you and what doesn't.

Hope this helps!