It's time to transform your ghost images into something more spooky- Try these steps to making your ghost image creepier:

Crop out any large areas of dead space, or any messy edges on your backdrop.
Image---> Adjustments---> Black and white. Play with the sliders to increase contrast.
Image--> Adjustments--> Hue & Saturation. Click "colorize". Select a nice brown sepia tone, if you want an old western look.
Image-->Adjustments-->Levels to make sure your contrast is on point.

We will create a non-destructive vignette:

Create a new layer.
Get a black paint brush.
Change your paint brush to a large size with 0% hardness and about 10% opacity.
Begin to brush the corners and edges of your photograph on the new layer.
If it is too much or looks strange, you can use the eraser tool to fix the photo.

While it is not a "ghost" image, here is a good before and after shot with spooky editing: