Your lineworks are really neat.
Your characters and designs looks quite interesting as well.
If I'd have to call your weakest point, I'd say colors. All the rest is great, but your use of color doesnt seem to be on the same level.
The picture with Garrosh for example:
The blue in the sky vs the reds of the rest is basically a good old dramatic and suspensful combination, but the values are kinda off.
I'd say it's a night scene, so make the sky dark! The fire is propably the brightest part in the picture and Garrosh needs to be dark again to pop out against the flames.
If I might suggest a nice practise:
Check out some pictures in black and white and concentrate on the values.
What is bright and how bright, what is dark etc ? B/w movies are also very interesting since they have neat compositions.
To round it up, Make some thumbs or redraw photos just with white, a medium grey and black to analyise which areas are bright/dark.