Illustrious usage and notes:

Positive prompt: jill valentine, 1girl, short hair, brown hair, blue eyes, breasts, tube top, bare shoulders, skirt, clothes around waist, boots

I suggest using the above tags as starting points and change them accordingly by removing tags you don't need. Most of them aren't actually needed.

If you want, or do not want, the tactical gear version of her outfit, then add this to the positive or negative prompt: suspenders, utility belt

For full prompt examples, look at metadata for the image uploads.

Jill Valentine [Resident Evil 3] Illustrious

#Mature Female