To start this painting out I used a basic grid to enlarge the rough outlines of the skull and candles. I took photos of the actual skull with the drip candles on top that I burned. It was actually four candles that I used. Two just didn't produce enough wax for my taste.
The yellow background is just an acrylic paint. I like to use acrylics for blocking in large areas at the beginning, and for under-paintings in general since they're generally cheaper and dry much faster than oils.
More details on the wax drips again and some shadows added here on the skull. Thin paint and really small strokes work best for bone texture to me. Slow and steady and cautious of overworking. Bone isn't smooth and should never just be white. The texture of the canvas helps a lot too when doing these subtle details. Far away it looks intricate, but close up its pretty much just loose brush strokes.
I originally thought of putting some swirling smoke on the top of the candles like they were just blown out, but I thought it best just to leave it be. The smoke would most likely have to go toward a corner, and that poses a threat of moving the viewer's eye out of the picture. Be careful of corners!!
And we're done!!
The final piece after the glaze and all. The glaze I used was a Windsor and Newton glazing medium with a liiiiiiiittle bit of yellow oil paint added. Notice how it makes the skull look right at home in the desert in comparison to the photo above it. Be sure the painting is thoroughly dried before you add a glaze. If you don't the paint will blend with it and possibly mess up your work. A glaze really helps to tie a painting together. If you struggle with having a painting that just looks like stuff is painted on top of other stuff, try a glaze. It will probably surprise you how it can magically make everything look natural and uniform.
Added a contrasting signature and its off to make a wall happy.