For best outputs and usage:

Sampler: Euler a

Steps: 50, cfg 4 ~ 12, CLIP skip 2

This model has its own VAE: XL_VAE_C1.safetensors.

For the neg prompt: simple negs or just nothing will do. Example: "bad quality, bad anatomy, worst quality, low quality, low resolution, extra fingers, blur, blurry, ugly, wrong proportions, watermark, image artifacts, lowres, ugly, jpeg artifacts, deformed, noisy image, deformation, skin moles"

For the pos prompt:

Keep the prompt simple, don't use extremely long prompts, focus on what you need

Use "Pixel Art" at the start or in the beginning part of the prompt, this way you can be sure to achive a pixel art type of image

Use words such as 16 bit, 32 and 64 bit to help the checkpoint understand the style if you are having a hard time getting pixel art

It's preferrable if you don't use words that imply a style that is very different from pixel art, especially in the beginning part of the prompt, prompts such as: realistic, Photography and hyper detailed may damage the pixel art aesthetic, use those only in the last parts of a prompt (if you want to use them at all)

Pay attention to the LoRAs you are using, some may completely remove the pixel art style from the image

The model understands keyword like "detailed", "best quality" or "masterpiece" and they actually may increase the output's quality.