My steering wheel has a lot of play. When I'm driving I have to turn the wheel further than I should have to to actually turn the car. This makes small corrections pretty difficult and lowers the amount of control I have. What could cause this?

 

Worn tie rod ends, worn idler arm, worn pitman arm, worn center drag link, worn steering box, worn rag joint.
Typically you can band-aid this for a little while by finding the pin near the rag joint, and slipping a 1" length of rubber hose over the pin. If this helps, then start by replacing the rag joint. If it's not much help, then replace everything else I just listed.