My theory: Never settle.

This applies to all relationships, friendships, romantic, sexual, everything. You should create an abundance mentality, and choose to let in those you love and those who love you and respect you back. I learned this lesson the hard way. I had a friend who I never really liked, and who never really treated me well, or engaged me in a way that allowed me to truly open up and be myself, but I stayed friends with him only because I didn't want to be alone. I curbed and suppressed myself so he would like me. I was his lap dog and his yes man. It was pathetic. So all those years I considered him my "closest" friend and I didn't really seek out other social circles or people. That's not a good way to look at things and it's not a good way to live. Also, just because you do stuff with someone, go out to eat on occasion and watch a movie, doesn't make that person your friend. You can easily find pretty much anyone who'll do that with you.

You should always have options, and if approaching new people is the issue, you need to get over that and network. That's what I'm doing. Never be friends or get into a relationship just because you're lonely, and it seems like there's nowhere else to go. There's always somewhere else to go.