Twilight is best dragon trainer. That big lug on the right doesn't stand a chance. Spike'll outmaneuver him and torch him like nopony's business, all thanks to Twilight's training.
I love her hair here. Also, nice touch with the cloth. And the design of the one on the right is interesting. He's almost missing a neck, but it's not impossible for dragons and such. If anything, Spike could use just a little bit more focused detail, but it's okay. The background and the large wing, however, have just the correct amount of. Well done!