Shooting night for day usually isn't too big of a hassle, but the key is to not have the sky or sun in the shot. It's mostly color in photos that tell us it's "night." Back in the 80s they would render everything in a heavy blue cast, and it still works, really. Nowadays you mostly desaturate the image and add a hint of cold cast and then maybe underexpose it a slight bit.
For the lightning it appears that you did some kind of painting with a soft brush along with compositing? What you can do it google search for lightning brushes people have made and just be conservative with it.