We'll begin this tutorial, by creating a new canvas at a size of your choice with a dark background. I will be using white for illustration purposes. I used "ValleyGrrrlNF" with a size of 87 pixels. Type "Diamonds".
You will now have to make a diamond. To make a diamond you will need to go here. Then learn to create a pattern by going here. Or download the diamond effect here. Once opened, Simply open you "Styles Palette" and apply the style to your Text.
Now that you have your text, you can now right click on the text layer and select, "Blending Options...". Go ahead and click on "Pattern "
Do not click OK yet... still more to do.
Now go ahead and click on "Gradient "
Click "OK" .
Now just simply add some twinkles to make it really glow and your done.
Click to enlarge