Extroverts, Introverts

Sometimes I feel like I'm split.  I'm neither an introvert or extrovert, but somewhere in between.  When I'm with people I'm comfortable with and know, I'm a complete extrovert and am completely comfortable with myself and other people (friends and strangers).  However, when I'm on my own in some new social situation, I'm totally shy, and I just want to curl up in the corner with a sign that says, "I DON'T EXIST."
It's because of this I feel like I have a general idea of what both an introvert and an extrovert feel.
I have absolutely no qualification to say what I'm about to say, this is pure observation/personal experience.  Feel free to chuck anything that isn't applicable to you out the window, because after all, this is me, and you are you.  But, for what it's worth...

Extroverts,
when you're in the that "zone," where you're in a social situation and utterly owning it, sometimes it's hard to remember or admit to that kid in the corner who's clearly uncomfortable and probably not having a very good time.   And even if you go over and talk to them, it's usually a one-sided conversation.
You have to remember introverts despise small talk.  I'm sure you're telling a very interesting story about when you fell off your skateboard but they're probably sitting there going, "Oh gosh now I have to make a witty comment back what should I say what can I say someone help me please."  (at least, that goes for me).  They'll probably just laugh awkwardly, force a smile, and say, "Cool."
So, instead of forcing you're (most likely wonderful, but slightly intimidating) self onto an introvert, try taking it slow.  If you're with friends that all know each other, and someone's an outsider, try to make space in the social "circle," and keep the conversation away from talking about past memories or laughing over inside jokes.  If you're talking about a certain subject, try asking the introvert, "So, what do you think?" and make sure you respond to their response.  Let them know you want to get to know them better, and aren't just being polite (something I find as an introvert is when people are just being polite, I feel there is no need to "get close" with them so I just give up and speak as little as possible).
And remember, introverts like little tastes of society and then alone time.  If they want to leave, don't stop them.  And above all else, just take it slow.  Introverts hate to be overwhelmed.

Introverts,
how easy it is to hide yourself from the world.  But, please, don't do that.  Don't hide behind your shyness.  It's very hard for an extrovert to include you in a conversation when you don't at least try to participate.  Give them something to work with.  I know it's hard, but try actively taking a small social risk.  Jump into a conversation.  The worst that will happen is an embarrassing moment, and in the long run saying something stupid never killed anyone.  Everyone, deep down, is just as uncomfortable as you, some people just ignore that feeling better then others.  There's nothing wrong with being shy, just don't let that shyness rule you.  Open your mouth and give your opinion, introduce yourself to a random stranger once and awhile.  Really, there isn't any damage you can do that is long lasting or irrevocable.
Also, whenever I see that one popular kid who just looks so happy with all his tight circle of friends I feel so hopeless.  How can I ever say hello to a group of people so tightly knit?  They clearly don't want another friend, much less me.
Just know, that is not true.
Just because someone who goes around with a close-knit group of friends, they're always on the lookout for a new one.  Just because they know some people really well, it doesn't mean I don't want to know you really well.  Everyone enjoys meeting someone new.
Don't hide, try, just once, letting your hair down.  Sure, you might embarrass yourself, but you might get a reward much greater then you could've imagined. 

^(OvO)^