For this project, I used my 9" x 12" stencil Tangled Pods ...
... along with matte gel medium, a spreading tool, masking tape, a soft terrycloth rag and a sturdy substrate -- in this case, I chose a large sheet of glossy cardstock that had already been monoprinted with blue and green acrylic paints, then had been used as a "catch-all paper" when I'd painted another paper orange.
After taping the substrate to my work surface, I covered it with my Tangled Pods stencil and taped that down, too.
For my next step, I spread a generous layer of matte gel medium across the top of the stencil, as shown in the two photos below. (I could have used gloss gel medium; in this process, either will work.)
After spreading the gel medium, I lifted off the stencil. See below--
At this point, I set aside the artwork to dry. (I cleaned the stencil immediately.) Since I'd used matte medium, I knew that when the gel became nearly transparent, it would be dry.
Once the surface had dried, I began to coat it with acrylic paints, first brushing them on, then using the soft rag to wipe away paint from selected areas.
The photos above show the starting stages. I went on to add layer after layer of paint, repeating the process, over and over.
The final piece is shown below. One of its layers was a metallic paint, which I used over about 2/3 of the surface:
To see my full line of stencils, please visit here.