Take off any spare doors and lean them against a sound internal supporting wall. Paint the outside white to reflect the heat and radiation, line the inside with newspaper so that you have something interesting to read before you fall asleep. Use the old Spiderman duvet cover to create a flap at the end to again stop nuclear rays penetrating into your shelter, Spidey is a super hero so they won't get past him. Fill empty milk bottles with water and store them in your shelter, also keep as many tins as you can.
If caught outside during a nuclear strike, duck and roll. In this way you will avoid being incinerated by the fireball, will dodge all of those nasty gamma rays and pieces of flying debris/veghicles being whipped around by the blast and positive and negative pressure winds. Don't forget to close your eyes, it might be a little bright at first and when the wind blows a bit of grit could get in your eye and potentially you could end up with a nasty case of conjunctivitus. Don't worry about any hair care products, combs or brushes: in a week you'll be bald, as will everybody else.