Tutorial: Neons
Add that underglow to your chops.
       
Neons
 
Difficulty - ***
Standard car... ready for neons.  
Make a new layer by going to Layer>New>Layer. And then use the Lasso tool and go around the car like the pic on the left.  

Fill this lasso'd area with a nice neon colour.. (We'll try bogey green, btu you can use any!).  

Then change the layer style to OVERLAY by using the little layer dialogue box in the bottom right of the screen.  

Righty... the neons layer is now semitransparent. and we can now grab the ERASER (E) tool and begin to eraser the bits not required.

Contrary to popular believe, neons don't light up fresh air, so ensure you rub out all the bits not required. Try to make sure you only keep the bits where it would light on the floor. ;)

 

Here we go.. finished product :D

You can duplicate the neon layer if you want to make the effect more intense. It works nicer on pics that aren't particularly bright, as it is hard to see neon's in the daylight!