Use good quality texture maps. Perhaps most important of all is your lighting, look for Poser lighting tutorials, also study photographic lighting. Also learn to use a paint program like Paint Shop Pro, Photo Shop, or Gimp. Post-work can play an important part, it can be used to change the contrast, gamma, clarity, sharpness, colour cast, and other variables. Also the joints in Poser figures are far from perfect, and often need some attention in post-work, smudge, smooth, and clone brushes are useful for that. I suspect that fygomatic does quite a lot of post-work on his images.