There are a bunch of tricks typically used to get GANs to produce more realistic images in a more efficient and stable manner. I would suggest checking out this GitHub page for a list tricks that can help improve quality for you:
GitHub - soumith/ganhacks: starter from "How to Train a GAN?" at NIPS2016
ganhacks - starter from "How to Train a GAN?" at NIPS2016
Hope that helps!