I’ll give you a weird secret. After you put the glowing object on a dark background, surround the white parts with a halo of highly saturated color. Observe:
It doesn’t have to be that blatant- smaller outlines of color, blended properly with the background, can make an equally effective glow-y look :)
I am Silver Tongue, I am an artist. I have many characters and you can check out my art in the art tag. I occasionally practice witchcraft though I don't do anything too complicated. I am girl 2 and don't know what else to put here.