[i speak in math]

Double click on your new layer (the one from the first step) to alter its layer style. Add an inner glow (your choice of colors) using a blend mode of linear light and size of 10 px. Add an outer glow (again, your choice of colors) using linear light and a size of 30 px.



To make the light a little more interesting, we will alter the original curve a few times. Use the direct selection tool to click and drag your path in interesting ways. Reduce the brush size to 20 and stroke your path again



Repeat a few time with brush size 10 (3-4 times should do it) altering your curve slightly each time. You should end up with something like this.