Made a mask of the sky and created a curves adjustment layer to get the background darker.
step 3 of 6
Created a new layer and filled with black, then set the opacity to 65%.
step 4 of 6
Created a new layer, filled it with black and then set the layer mode to color dodge. Painted all of the lights with a soft low opacity brushes with many layers of painting.
step 5 of 6
Another black layer set to color dodge and painted with a soft brush.
step 6 of 6
A new blank layer was set to normal and painted with a white brush to create the light effect.