Layer duplicated, desaturated, lowered opacity to gray down
step 5 of 14
A layer of dark blue was added and set to overlay. It came somewhat from an old tutorial I used at one point, but I can't find the link to give them due credit.
step 6 of 14
Another layer-this time black to darken lower perimeter areas
step 7 of 14
Early on I used select>color range to isolate the sky, then I saved my selection for this step, where I filled the sky with black.
step 8 of 14
I made a star brush & set it for random dispersal.
step 9 of 14
Stars added to the sky
step 10 of 14
Sign added, lights added to car using first a yellow gradient the a red gradient. Sign thumbnail ctrl/clicked and color changed to a more accurate local coloration, then lettering selected & brightened. Distant headlights added & blinking tower lights.