1) is huge. I really started coming out of my shell when I went traveling - here I was in a foreign country where nobody knew me and I'd never see any of these people ever again. So why not talk to the random person at the train station? Why not walk up and introduce myself to some strangers at the bar? And with that practice I started getting better at it, which made me more confident, which made me more comfortable with it, which made me better at it, and there we have that positive feedback loop.