To glow is to give off a steady, low light but without a flame or fire.
Ex: After the lights went out, our room in the hostel was not very dark. Lights from the street and the smartphones of our roommates all continued to glow. It was quite difficult to sleep.
Ex: For Christmas, Shandra bought her nieces some toys that glow in the dark. You turn off the lights and they seem to give off a green light themselves.
A person who looks very happy and more attractive as a result is glowing. A very positive review or description can also be described as glowing.
Ex: When Sheena came back from her holiday and learned that she was being promoted, she was just glowing. I've never seen her so happy.
Ex: Boris is still looking for a job, but he should find one soon. His last supervisor gives him a glowing recommendation every time a hiring manager calls her.
To shine is to give off a bright light, or to reflect a bright light like water, a mirror or steel in the sun.
Ex: Chad prefers living in the southwest because the sun shines there just about every day. It's always bright and beautiful, even in February.
Ex: Mo took a beautiful picture of the beach yesterday. The water was shining in the sunset and the clouds in the sky looked purple.
Something that has a clear surface and shines in the light is called shiny. A person who does very well at something, usually better than other people, also shines. To shine some light on a topic is to give more information about it, especially when you are clearing up some misapprehension or misunderstanding.
Ex: The jewelry was mostly cheap and simple, probably not even silver but just steel— but it was shiny, nonetheless. It was hard not to notice it in the sun.
Ex: Pete is pretty shy most of the time, but when we're sitting around the fire and singing, he really shines. He's got a beautiful voice.