I tried out a new-to-me mixed media technique for this ATC and am rather pleased with the results.
Take some brown (kraft) paper, an inch or so larger all around than your finished piece, and crumple it up. Crumple and uncrumple a few times till you like the texture.
Cut a piece of iron on interfacing to at least the size of your finished piece, and iron it on. The paper now feels more like fabric than paper, and won't tear where the interfacing is adhered.
Turn the paper over, raw an outline of your finished piece in pencil. Stick some pieces lace or other deeply textured textile on - I used gel medium to stick mine.
Take some perle embroidery thread - different weights would be nice, I only used one because an ATC is pretty small - and sew. I used stitches to ensure that the lace was anchored, and also as part of the design of my finished piece. The stitches are simple - blanket stitch, fly stitch, straight stitches and french knots.
Take some gesso and paint over everything you've done. I know, you just did all that embroidery - don't worry, it will all look good in the end!
Once the gesso is dry, paint over it with dark acrylic paint - I used Golden fluid acrylic in Paynes Grey (which I think is more of a blue!). Be sure to get the paint into all the texture - this will probably take 2-3 coats.
Once the paint is dry, rub all over with a gilding wax - I used Treasure Gold in sapphire. You could use rub'n'buff, or a Liberon product.
Finally, highlight all that texture with a contrasting colour of gilding wax - I used Treasure Copper - you need to have a very light touch for this part as you need to avoid getting the contrasting colour on the background (as far as you are able).
I'm really pleased with the end result, it has 'wow' factor - I will use this technique for other projects.