Good: ‘killing your darlings’, ie cutting things that don’t serve the story even if you love them, is a very valid idea. The trick is knowing what serves the story (tip: it’s not synonymous with ‘advances the plot’)
Bad: any kind of prescriptive story structure. Hero’s journey, story circle, save the cat, etc.
Ugly: ‘write every day’. Not everyone can, and not everyone benefits from it. Touch grass.