I'll be using the picture below. First, create a new layer (Shift + Ctrl + N) and set it to screen.
Select your brush tool and match your settings like mine:
Select a color and start using the brush tool (on the new layer), mine turned out like this:
You can get a better look if you duplicate the brush layout, this is what I got:
Now all you have to do is duplicate your background image, set iton top and set it to overlay.
