After doing this for years, I no longer worry about preparedness. In the extremely unlikely event that I mess something up, I just laugh, everyone else laughs and I start over. I am also confident in my ability to sing pretty well, barring illness, even if I don't get to warm up as much as I would like to. Even on terrible weather days, like we have today, my voice works, and my brain works, and audition disasters are practically a thing of the past (knock wood).
You would think that would make auditioning a piece of cake. But no. My standards are higher. I want to deliver moving, emotive performances that make people stand up and take notice, even if I look like a drowned rat, it's 10:15 a.m. and the auditor spends the whole time huddling over her coffee cup, barely looking up.
I am experimenting with different ways of "bringing it" in auditions, and today my experiment had me directing all of my attention at the imagined space and imagined people that would be in the scene if I were actually in the opera, instead of in a run down dance studio performing for the person sitting behind a table at the opposite end of the room. In other recent auditions, my attention has been directed more inward towards the emotions that singing the character's words make me feel, but I've found that deeply unsatisfying after the fact.
I, personally, find it very challenging to chew imagined scenery, but 90 minutes after my audition this morning, I feel much more satisfied with my performance, so I guess I'll try to do it again next time.
N.B. If you know any professional opera singers besides me, give them some extra love and kindness during this time of year. Audition season exacts a very high toll on all of us emotionally and financially.