Compare cities in terms of cost of living, demographics, weather, job opportunities and culture. Read the annual reports from "Forbes" magazine or from "The Atlantic" on the best cities for new college graduates, and use a cost of living calculator to find out how far your salary will go in a new city.
Use your college's alumni network. Whether established professionals or young graduates like yourself, alumni are bound by common experience and strongly inclined to share in their knowledge and open doors. Join the Alumni Association, attend events and use internal job boards to connect to the professional community in your new city. The career center can also help you begin to develop a professional network.
Join with friends in planning and making your move. Loneliness in a new city is one of the likely obstacles you will have to overcome. Making the move along with friends can help with that. If you plan to live together, you'll benefit from being able to pool resources for a security deposit and avoid the unknowns of having strangers as roommates. And if you move to an exciting city with many young people, some of your college buddies will surely want to come too.