I choose a "flat" site, (I use the side of my shin, as I live in jeans). I clean the skin with surgical alcohol, to remove any grease. Heat the skin gently with a hairdryer on warm. Apply the patch, then press down, warming it with the hairdryer. It helps the glue to stick better.
hedwig- are you sure that it's ok to stick a patch on your shin? I have always thought that they had to be on an area that had a good layer of fat underneath to help absorption- so buttocks or hip areas.