If you have a hobby, look for an organization or group to fill the hobby such as Scrapbooking - attend all day workshops (true, you mostly stay to yourself, but you still can mingle a little and get to know regular scrappers) - Look into a local craft store for scrapping or other craft workshops - Google Scrapbooking to find businesses like Creative Memories where consultants hold workshops.
Do you like to read? Check with the local library to find a reading club to join.
How about checking the local Community Education for a night class to take on something you are interested in?
If you like to garden, check out a Master Gardener's club. There are clubs for so many things, even photography.
If you like to sing, maybe check with the local theator, college, your church ect. to join a choir.
Do you like acting? The local theator may have open auditions for a play - there is so much down time between practicing individual/group parts that you would have lots of time to meet and visit new friends.
If you belong to a church, join one of their bible studies or ladies aid groups.
There are service organizations such as Habitat for Humanity, Hospice, ect. that you can inquire of helping with projects.