Cut and rip old clothes from your closet, or buy an outfit from a thrift store. Consider a themed zombie costume, such as a zombie bride in a wedding dress or a tourist zombie in shorts and a Hawaiian shirt. To look like you just stepped out of a grave, smear dirt or ashes over the clothes. For another distressed finish, run over the clothes with your car. For bloody clothing, spray a mixture of water and red food coloring onto your costume.
Start with a pale face by applying white makeup. Add dark circles around your eyes with green and brown eye shadow. For wounds and scabs, use latex wounds found in a Halloween or costume store, or create your own wounds from liquid latex. Do not forget to apply some fake blood on the face.
Make your hair as messy as possible. Tease it with a comb. Add some debris such as twigs and leaves. You can also add some fake blood and give yourself a fake head wound.