Colored pencils are probably your best choice when doing this technique because the thin vellum will buckle easily with watercoloring. Here I used markers and a tiny bit of watercoloring with a brush, but went very easy on the amount of water. I used my white gel pen on their eyes and teeth for some "pop".
Adhere to a lighter piece of CS the same size or slightly larger if you want the vellum "framed". You'll need to use brads or find some punches or embellishments to cover glue if you choose to adhere it that way. I ran my Real Red Mat and Basic Gray card base through my Cuttlebug using the D'vine Swirls folder, one of my faves, it goes with almost everything! I did a direct to paper technique with my white craft pad over the embossed swirls to really show the texture.
I always try to make my choice of embellishments echo some of the other elements in the card (rather than just picking something because it's cute!) so I chose this dotted ribbon to pick up the spots on the back, the brads, the white dots from the heart and the flower center, etc. All these things, whether the viewer realizes it or not, draw the eyes around the card, and creates a much more visually appealing whole. I feel like since I started making sure everything had "an intent/purpose", my cards improved dramatically. I'll be showing an sample I feel illustrates this really well tomorrow, please check back! :)
* if you don't have vellum, you can also do a reverse image with a rubber brayer or a large bold "reversing" stamp like a square or rectangle by kissing your image onto the reversing stamp, then pressing it to your paper (but mine was not large enough for the giraffe, it is a tall image). This is better for being able to color and not having the smearing or adhesive issues you do with vellum, BUT, your second image with be lighter as it comes out looking "stamped off". So there are advantages and disadvantages to both...