Oooh, balance is one of my favorite words! It says don't run to either extreme.
I think a way to fix this is to consider the of person you're talking with. I say WITH because conversation is a two way street. What kind of person is the other person; are they a real talker or are they quiet, shy?
Another thing to take into account is what you're saying. Do you know what kind of details to leave in or out of a story? As I write this response, I'm also thinking about what I want to relate to you and which are the most important facts. Look at the way you wrote your post. Conversation is like that only it's done verbally. You have to be able to think in your head as you go along. I always do better on paper- thank goodness for the "back button!"
I have to work up my nerve to talk to new people. Itry to start with short conversations. If they look like they want something longer and I'm uncomfortable, I'll make an opportune excuse to cut 'n run. "Will you excuse me? I need to make a call before it gets too late."

Yeah.. I usually say something really stupid and everyone goes silent. I mean, You cant help it. You are who you are ya know? I usually hang out with people who know me for me so i don't have to meet new people lol.. But yea i totally get what your saying. Don't get so hard on yourself though, it just makes it worse!

ah i get well freaked out when around loads of people. i tend to put my foot in my mouth, or so i see it. i thnk im getting better...not sure tho. id much prefer being quiet tho, i thnk people get tired of louder people kinda quickly. so if i wer u, i wouldnt look for a balance, just be happy being as u r. cliche i know, but its true!