Well, I haven't finished the edge yet, but other than that, it's finished! I'll post a photo first, then ramble a bit about how I did the finish, in case anyone wants to know...
I started with a fine rapidograph pen with black ink to delineate some of the outline, which helped separate foreground/background. Next, I painted in the background with Fiebing's Ox Blood stain. After that, I used Tandy's Midnight Black between the design and background to help the design stand out a little more. I used the same black for the dark places in the eyes and inside the jawline on the right side. Then I started the color with Tandy's Hi-Liter Saddle Tan with a #0 Windsor & Newton brush on each little scale of the dragon, including the belly scales. Then I went in with a bit of their Briar Brown color to darken up the nooks and crannies. Pretty much the same process and colors with the skull, also - just used a bigger brush.
The mouth and tongue are a combination of All-in-One Primrose Red, and Cova Colors Cherry and White. No particular technique, just picking up paint back and forth until it worked out not so bad. The eye is All-in-One Cactus Green, Cova Colors Kelly Green and Yellow. The teeth were all Cova White with Turquoise. The skull teeth, also. But I had to go back in and mute it with some more white before it looked halfway decent.
I love the look of the Ox Blood stain on the background. I saw it used on a YouTube video, and really dug it. I used a very uneven backgrounder tool to get the weird texture, because I was hoping for that sort of mottled look.
Thanks for all the help and advice, everyone - I'm very happy with the way it turned out. Wish I should show it off in person - photos don't do it justice.