This thread primarily deals with NovelAI (henceforth NAI)'s image generation, so all links below will focus on their service.
Danbooru Tags
https://danbooru.donmai.us/wiki_pages/tag_groups
Since NAI's image gen uses danbooru's tags for categorizing images, you may get more control over your results by using the appropriate tags.
Tag examples
https://rentry.org/faces-faces-faces
https://rentry.org/xnpkp
Thanks to a helpful anon for making these!
If you want to discuss image generation indepth, consider going to /g/'s Stable Diffusion threads.