Normal maps only work for (very) small details. You either want to increase poly counts or add tessellation. Other than that, its all up in the air. I prefer using 2048 texture maps for most things, though 4096 would be better. Hardware needs to get a bit better before we can start using 4k textures everywhere though, heh.
Other than that, make sure everything is scaled 1:1 as to how it would be in the real world.