This is the workflow I usually use as a base for any type of upscale. In addition to this workflow, you'll need specific model to upscale. Remember to download them.

General rules:

-The workflow is intended as a basis for upscaling, not for image creation.

-You must (always) select the steps and the cfg based on the model you're using. The positive and negative prompts. Denoise is really important. Other things don't change.

-There are custom nodes; you can add them to have my workflow once opened.

I haven't been in this wonderful world for long, so I still have a lot to learn. I might update it over time if I find something isn't working well.