When you cover the whole surface of your glass with a light coat of paint and blend it smooth, this gives you a lovely surface on which to trace and shade - one that's much, much better than bare glass.
2. For greater accuracy, sketch your trace lines with the glass on top of the design, then reinforce them later with the design on one side where you can see it.
This gives you much more control than the usual method where, with the glass on top of the design, you try to paint your trace lines all in one hit.
3. Learn to shade before you trace.
Here's a brilliant way to do this. Paint an undercoat and let it dry. Copy-trace the outlines and let them dry. Reinforce the copy-traced lines and let them dry. Now take the same brush you used to paint the undercoat. Paint gentle, light stripes over the whole surface of the glass. While this paint is still wet, take your blender and use it to soften your traced lines into gentle shadows.
It's amazing. Loads of demos on my blog.
4. Create subtlety and interest by varying your highlights.
Yes use a sharp stick by all means. Also use different widths and hardnesses of hog-haired scrubs. And lastly also use your fingers to soften existing highlights.
(Keep your fingers dry and clean at all times, and wash them thoroughly afterwards.)
5. Add depth by shading and highlighting on the back of the glass as well as the front.
With the right amount of gum Arabic in your paint, it won't matter if you paint the front, then turn it over and shade and highlight on the back.
You can fire both sides in a single firing.
So you don't just add depth to your glass painting, you also save time and money.
