My friend 
My sister, Lynn, was my first introduction to friendships through sisterhood. She was 8 years older than me and was the only person in my life that loved me unconditionally - not my mother, or stepmother or my father, just Lynn. My life was pretty lacking in enough love from those around me other than my sister, that I suffered from a deep emotional black hole that led to co-dependency and love addiction in my teen years to 30's. It also made me a lousy friend, because I would drop a friend to be with a man 24/7. Not proud of that time of my life.
Now I have more to give as a friend and a little better understanding of how to nurture friendships, but its hard because most of my friends are like me, very independent, creative, busy women. We forget to nurture and give to each other regularly.
Society doesn't really teach us how to be good friends, there aren't many movies, tv shows, books on the subject like there are on primary love relationships. I was never taught by my mother, stepmother, sister, church ladies, teachers etc... on the basics of friendship.
So even though I Suck at Friendships, I know it, admit it and doing my very best to be better one day at a time and one friend at a time. Maybe there is a self help group for me somewhere! :)