There are no secrets.
This is a basic usage of "SelfIllumination".
However, "SelfIllumination" does not illuminate.
"SelfIllumination" is the effect which keeps the brightness of color original in the place where the lights do not illuminate it.
So, first of all, you need to draw the picture that seems glowing.
The rex explained how to draw it in a reply before.
However, if you use "layer style", you can draw it more easily.
Make the glowing part in the separated layer.
Next, make a alpha cannel for "SelfIlluminateionMask".
Make a black layer and set the layers that only the glowing parts can be seen.
Then, make the alpha channel from it.
And. ajjust the levels of brightness and contrast of the alpha channel.
Adjust the parts to glow become white.
The rest, set the same texture which add the glowing parts to "Diffuse" and "SelfIllumination", and set the texture which has alpha channel for glowing to "SelfIllminationMask".
(By the appended texture, in order to make easily to understand, the textures which are different in "SelfIllumination" and "SelfIllminationMask" are used.
If the basic texture has the alpha channel for mask, you can set the same texture to "SelfIllumination" and "SelfIlluminationMask".)