Do not forget that you may might like to include a ghost in one of your stories, a character who has passed from the world of the living, but who will not actually leave!
Ghosts come back in a variety of shapes. Some are drawn simply, almost like a bed sheet floating in the air. The ghost above is especially ghosty when you see right through him. Transparency accentuates his spirit form.
Alternatively, a ghost may still have color and even retain the appearance of her form from when she was alive—although putting something like her long locks of hair up in the air gives a wonderful feel of being “other worldly.”
One of the most frightening ghosts is the one who returns from the grave dressed in a dark cloak and cold, rattling chains. His skeleton rattles, too, when he walks, of course!
Remember the world of the non-living when you are looking for story characters. They are just as eager to be included in stories!