Mighty good question! I'd like to know too. So far, this is what I've managed to learn...

For me, people will always make me feel uncomfortable or tense, no matter if I want it or not. They don't need to do anything in particular, just their presence is enough...That's when the anxiety can kick in. The physical signs are not so noticeable, though the 'ear ringing' is the worst (not sure if that's the right term, but then you are being able to hear your breathing, but may not hear what you're saying), which I don't know when or why happens. I also noticed that my palms can get very sweaty, the mouth may dry...I don't really care about myself in these situations, but to escape, you see.

I have the habit to cover my mouth, to look down on the ground and avoid eye contact. I also need to pretend sleeping or act like sleeping on a packed train/bus, otherwise I'd either find the people annoying/bothersome or ridiculous - and when I find them ridiculous, I often have the desire to laugh, but I don't want to! So to avoid laughing at people at those times, I just try to sleep and close down...

I realized that it is highly unlikely that I won't ever feel 'stressed' around people. I can't bear it if there are more people around. I'm hiding it well, but it still sucks, especially that ear annoyance...

I noticed that the anxiety happens when the train is packed, and I'm more relaxed when the wagon I'm in is quite empty with just a few (less than 3-5) people in a way that they can't see me...So, people will always make me feel uncomfortable or tense, no matter if I want it or not (repeated sentence).

As far as I read, the best thing you can do is learn to control your anxiety from getting out of hand. You can't get rid of anxiety (as a little of it is completely normal and healthy), but you can lessen its effect or its toll that it takes on you...

So how do I cope with anxiety?

I had lived a very sheltered life, so the littlest bit of social stuff tires me. To me, it takes a lot of effort and courage to be able to talk to people, and yes, to just open a door in a building and ask something from someone, or to go doing something and venturing out into the unknown. (Though with familiar places, no problem.) The shy awkwardness is always prevalent, so I'm usually ignored...others, of course, don't recognize much of the (inner) agony of this state...

There's this one guy in the class who keeps talking to me, sometimes (though not lately). I have no idea why, but this might help with anxiety...to be able to make smalltalk and social interaction, disengaged from your worries. To not take everything seriously and don't try to control every aspect of your life...Also, to not be overly self-conscious and just laugh if you mess up (for example, when you stumble), and don't make a big deal about it and get out of the 'perceived error spiral'. Just a little talk with a person, even if only about the weather or just saying "hello" - while it may seem banal and useless -, might get you into a playful or elevated mood.

I used to skip school and be truant (which I still do when I can't help it), but nowadays I try to stay focused and don't escape from pressuring tasks or ordeals. OK, that's a lie , but if I do escape, it's because I can't concentrate or focus on it and want to do something else...I know that when anxiety crops up, the experiences you get will not be very good, so you may need to adapt to dynamic changes of what would you like doing when such a moment happens. When it gets 'unbearable', I need to retreat, no chance.

But, regardless of how you feel and think, it's still important to participate in life. Wallowing in anxiety is the quickest way to give it power. So try to have some willpower, though I know it is finite and hard to maintain.

Not dwelling and loosening up is the key (don't overthink, not taking everything seriously, making fun out of life), but that's just difficult in its own right (to get a lil carefree like a child). Find a place for the anxiety to exist, don't mind to have it there, and accept what happens. Try to do deal with cognitive distortions to transform or lessen the effect of negative thoughts. Keep yourself on the top. I know I'm not the one to talk (I avoid people in forums/online and real life similarly), but thought this may help.

You don't need therapy or drugs to do this, maybe write into a diary your thoughts/feelings and monitor the changes, check out your thought patterns. When we get anxious or stressed or distraught, it's very hard to implement any of the things we know we should do, that's why reminders or someone to guide us is important.

Sorry if none of this have helped, I just had to rant a bit...