Recommended settings:

Sampler: Euler, Euler A, DPM++2m Karras

Steps: 20-30

Upscale: 4x-Ultrasharp

Denoise: .35 (35%) or .50 (50%)

CFG Scale: 3-5

Positive Prompt

for basic prompt just add

masterpiece, best quality, amazing quality, very aesthetic, absurdres, newest,

If you want just a hint of more depth than a full 3d look then just add

realistic shading

for additional 2.5D effect add

photorealistic, realistic

Negative Prompt

lowres, (worst quality, bad quality:1.2), bad anatomy, sketch, jpeg artifacts, signature, watermark, old, oldest, censored, bar_censor, (pregnant), chibi, loli, simple background,