Another trick to get you clicking the shutter button more often!
Firstly, consider a scene where you like to have your doubles with. Next, secure your Diana+ on a tripod and shoot. After taking a shot of the scene (which is the first layer), it’s now time for the second one but this time have someone to be included on it and without winding your film, cock the shutter and just take another shot. For self portraits, it is always handy to have a cable release.
That’s it! you can expose the frame many times as you want to get that ghostly effect! Just select the smallest aperture to compensate the layers. Have fun!