Open your photograph in Photoshop. Create a new copy of your photograph so you are not working with the original. The copy will be the same, but your origianl photograph will be retained on your hard drive. To create a new copy, go to "File," "Save As" and give your photograph a new name.
Press "Control" and "J" to create a duplicate layer of your photograph.
Select "Filter," "Artistic" and "Neon Glow" from the menu bar.
Select a color you think will enhance the photo.
Input "4" for "Glow size" and "18" for "Glow brightness." Glow size indicated the thickness of the line of neon that you are adding to your photograph. A smaller number is equal to a thinner line; a larger number will cover more space on the photograph. Glow brightness lets you determine how bright you want your neon color to be. The lower the number you choose, the fainter your neon color will be; the higher the number, the brighter your neon will be.
Select "Overlay" from the list of modes provided to complete your photo. If you are unhappy with your altered photograph, you can undo the overlay and neon by pressing "Control," "Alt," and "Z."