Just my .02,
DON'T BE SHY.
Look around, hang out in places, London City for example, and talk to people. Take the initiative if someone seems interesting to you, don't just sit there waiting for someone to IM you. The worst that can happen is they will block you, or grief you, heaven forbid, but then you can block them and move on, but by all means, just take the initiative and say hi to others.
Many times nothing comes of it, but often enough you meet someone quite wonderful. I know I have, and I've been a loner most of my life, until I got into SL. Since I've lived where I am in RL, over two years, I've not had the social life and the friends I've made in just a week in SL!
Give it a try, you have nothing to lose! No one can really hurt you in SL, unless you let them, and how lame is that?