When I am nervous, I may stutter more than I usually do, and I may feel very warm too. Then again, I always feel nervous when I am around people I am not comfortable with, so feeling those is sometimes normal for me...

The moment i feel anxious, i start biting my nails and fingers (the edges). At the same time i tap my foot up and down and react very fast on every little thing! No fly is safe when i am getting nervous!

All I do is Sweat. I don't really know why, I just do.

When I get super nervous I get that weird empty feeling in my gut and I start to pace. Most likely while I am pacing I will crinkle my forehead and bite my nails (both bad habits I can't get out of).

I have this very distinctive thing I do with my hands when I'm really nervous, where I ball them up into really tight, awkward fists at my sides. I am totally unaware of this when I do it, because I'm usually focusing really hard on something when it happens, but people always say they notice me doing my "hand thing." The other day in my theatre class we were doing monologues, and monologues are like the most stressful things ever, so even though I was miming my character being on the phone, I guess the "hand thing" somehow wormed its way in there, because when we did critiques afterwards, my teacher/director and several students mentioned it as something I needed to fix. Apparently, it's one of my worst acting flaws, because awkward hands when you act look super unnatural and I don't even notice I'm doing it, so I'm trying to be more aware of that now and plan out what my hands are doing. It's not just acting, though, I have been caught doing this for dozens of things, and whenever I do it people are like, "Were you nervous up there?" and I'm all surprised, like, "Yeah! Really nervous! How'd you know?!" and they just kind of go "You were doing that thing you do with your hands..."
Ugh! Such an obvious giveaway! Haha!
With less onstage stress, such as ordinary things like walking down the crowded halls or socializing, my cheeks get really hot, and I kind of draw into myself and fidget with my hair, or my clothes, or I rub my hands until they hurt. I will also begin giving extremely short answers, hide my face behind my hands because it feels like I'm blushing hard enough to turn the whole room red, or pretend I'm super busy on my laptop, or with a book, or with my homework, and then I try to make as quick of an escape as possible. I get really, extremely, painfully shy. It's a pretty bad problem too, because some people take that the wrong way and think I don't like them because I refuse to give them more than a few lines of conversation and do little more than answer questions. I really don't try to turn people away, and it makes me feel really bad, but people are scary! It is so hard for me to talk to them; they have no idea...

I cut my fingernails off... with other fingernails.