Visualization. Play the movie in your mind 10 or 20 times a day...like you're day dreaming. Picture the whole process from putting on your gear to getting in the plane, sitting on the floor, climbing up to altitude, seeing the door open, etc...focus on it and try to recreate the feel of it...do this as often as you can the week before you jump. It will help greatly as the whole process will seem less foreign when you get there...because you will have seen it a hundred times or more.