I'm playing with image transfers lately too. That's a bit eerie.
I take fresh photocopies (or even prints) from a toner-based printer. Placing the image down onto the surface I want to mark, I apply nail polish remover to the back of the copy. Using a spoon or brayer, I rub the image in, pressing harder in the areas where I want more detail + making sure the paper doesn't move during transfer. After a few minutes of this, I peel back the copy carefully.
Factors you can play with to achieve your own desired results: how much you saturate the photocopy, how long you let it sit atop the surface to be marked, how much/how hard you burnish it onto the surface, how long you let it sit after rubbing.
You can also experiment with the fluid you use to initiate the transfer. Though I've never tried it, I've heard turpentine, acrylic medium, and even blending markers can produce similar results.
As previously mentioned, you're transferring the mirror image onto the surface, so if it involves text or other considerations, you'll want to reverse the image.
Best of luck!