Civitai has a bunch of Lora's that might help with crispness? My favourites are Denoise & AddDetail. I'd also use a popular SD1.5 model like Deliberate (until sdxl is released). I always do highres fix, maybe scale 2x from 512 on a low denoise & see what you think.
There's also an after detailer extension I use for doing extra processing passes on hands/face etc.