Leghorn is the breed used for most commercial egg operations. They're nervous birds, and lay white eggs. Brown egg layers, like the Golden Comet, are calmer and more fun to have. Check with your county extension agent. They'll recommend sellers of good breeds for your area.
Good housing is important.
An electric fence around the coop will deter dogs, coyotes, and foxes. It will need electricity for supplemental lighting and heat, if you live in a very cold climate. Healthy chickens need lots of fresh water. A water warming device will prevent water from freezing in winter. One chicken will eat two pounds of feed each week.