For best outputs:

Sampler: Euler a.

Steps: 4 ~ 5, cfg 1 ~ 1.5, CLIP skip 1.

Adding keywords like "Masterpiece, best quality, professional photo" to the pos increases the quality slightly.

Use this simple neg "blur, blurry, worst quality, low quality, jpeg artifacts, poorly drawn, bad art, weird eyes, extra limb, missing limb, floating limbs, deformed, bad eyes, crossed eyes, disfigured, mutation, ugly, face distortion".