Lighting is pretty nice for showing off the costume. I especially like the posing in #1 and #3. The main thing that would be good is the background is pretty unspectacular. Bringing the subject away from the background and shooting with a wide open aperture would make it less distracting. Or if you can find a background that fits into the lore of the cosplay you're shooting, that's even better. Excellent cosplay deserves and excellent setting.