I'm a big fan of meetup.com
You can find groups on most anything you imagine. I love hiking, for example, and I'm constantly finding amazing people to go hiking with, planned hikes, all over the area, at least twice a week now. It's such a blast.
There's groups that go out and try different restaurants in the area, people who want to bring chihuahuas together, book club meetups, dancing meetups, spiritual meetups... whatever you want!
Do what you LOVE and allow your relationships to stem from your passion, rather than blindly groping around for a person out there somewhere. It's much easier to find friends when you enjoy doing similar things together.