Help with Shading and Highlights

I’d like a bit of input as to what I could do to make the shading and highlights on this wip look alright. The light source is obviously the fire. I have been drawing for six years, and I still don’t quite have the hang of shading and highlighting, so resources are appreciated too.
 

Want some advice on how to make this look as best as possible.

Broken link. Gotta cut the… referral code(?) out
 

… Never mind.  
https://derpibooru.org/916686

@Background Pony #F56A  
Broken links. God, I hate them.

My lazy man’s way of doing a night scene is just coloring a pic like it were daylight, then throwing a solid block of transparent gray-blue on top of it:  
 
But if you need to know about general shading/highlights, you can search ‘shading tutorial’ on deviantart and get a lot of pic references. Sometimes I’ll just do a random youtube search for pic shading and sit through a few videos to get more ideas on how people color their works.

Especially with a point source like a fire, you need to figure out where the light’s coming from and add shadows and highlights.

Look up Sycra’s video series on fundamentals of light and shadow on youtube.
 
That should fix ya.