How to easily create customized watermarks in PSE

Here are the quick steps :

First open a new file with transparent background.
Create a text layer with the text you want on watermark.
Customize it as you want. You may use bevels effect on the text layer from effects pallette. Add glow, strike etc by clicking on the icon one right side in the text layer in the layers pallete. You may add gradient if you want and customize it as you like.
Then just add this as a brush from Edit menu >Define brush. Now this will be added to your brushes in preset manager.
Whenever you want to watermark any picture, just click on Brush tool and choose the brush you created from top toolbar. You may also select different patterns from patterns dropdown and then just stamp them on your pictures. I am not sure if people use this or not. It was just a workaround which I got for myself.

Adobe Tutorial