Best not to tell us what we already know as in “I’ll be doing a short monologue for you today.” We know that because we probably asked for a short monologue. Figure out how you can use that short amount of time to its best advantage. You can come across as really disconnected or really nervous when you use standard phrases that don’t make so much sense in the moment. Being present and being comfortable rather than sticking to your script is the best practice.
At the same time, bookend your audition well. Live through the last moment rather than saying “Thank you” the second you’ve finished the last syllable of your last word. And don’t say “scene” at the end. That went out of style about 30 years ago. (I know some people are still teaching that but they’re out of touch.) If you’ve done a great job with your monologue that last moment will make it obvious that you’re done.