It is easy to look very dead with common household 'makeup'. Follow these steps to look like you were just exhumed.
All you need is:
Tissue paper (the gift wrap kind)
Light corn syrup (aka Karo Syrup)
Possibly some 'normal' powder makeup/eyeshadow and a grease pencil
Spray temporary hair coloring
Thrift Store Clothes
Miscellaneous Spray Paint
Step 1: Start Fresh
Start with a clean dry face wearing clothes that you can throw away.
Step 2: Hair Color
Use temporary hair color spray sold at Halloween time. It's inexpensive and is generally easy to remove. Use hair spray and gel to provide some 'body'. Don't forget your eyebrows.
Step 3: Wrinkles and Rot
Apply a thin coat of Karo (or other brand) of light corn syrup to your skin and then apply tissue paper (the kind used for gifts). Some additional corn syrup may have to be applied on top of the tissue paper to tack it down.
Make sure to create folds and lots of 3D relief. Accentuate areas where wrinkles would occur, especially under the chin and on the neck.
Step 4: Blow Dry to set
Blow dry during application to help set to your skin. It will still remain tacky but it should now feel more firmly attached to your skin. It can also be helpful to do some blow drying as you go, particularly if you are going to build up an area to be very thick: Apply a layer and blow dry, repeat.