No matter how much preparation time you get, start planning what you hope to accomplish by specific milestones. Even a few hours of preentry planning can go a long way. Begin by thinking about your first day in the new job. What do you want to do by the end of that day? Then move to the first week. Then focus on the end of the first month, the second month, and finally the three-month mark. These plans will be sketchy, but the simple act of beginning to plan will help clear your head.