At first: don't take this too serious. It works really well, but your checkpoint will mostly switch back to flat colors after the second image or so.
Put this in positive: (lifelike-realistic-theme, photo-lookalike)
and this in negative: 100%-anime-drawing-lookalike:2
Why "piss off"? Well, your checkpoints generate images on a base they were trained on and that negative prompt is like a punch in the face.
These prompts generate realistic images at the will of your checkpoint. If your checkpoint is trained with anime and real photos, you won't have any problem, but if it is purely trained on anime- or cartoon-images, you will get a mix. I tested it on "something" for SD and "deephentaiMix" for SDXL and decided to only upload the result from "something" to make it more believable, because "deephentaiMix" can handle "real" photos very well.
This time, this article is more on the funny side and not even close to serious. Have fun....
EDIT: i forgot to mention something really important: instead of "lifelike-realistic-theme", try "lifelike-realistic-lookalike" to get better results. Both work, but the second prompt is closer to get to the point.