I bought my dd a tall thin mirror from Dunelm for about a tenner - leans up against the wall and takes up no room. Not all rooms have mirrors!
I second the recommendation of sliders/flipflops for the showers - some students are manky and don't leave shower areas very clean. also a large-ish see through toiletries bag with a hanger/tab to hang on a hook for shower items - soap, shampoo, razor etc.
A small first aid box: I made up my own as the ones you buy have bandages and all sorts you won't need. I put in plenty of pain killers, small bottle of TCP, plasters, tubes of germolene, sudocreme, antiseptic wound wipes, sachets of dioralyte.
A towel rail/clothes airer. Again, you can get cheap ones from Dunelm/wilko. She can hang her wet towels on it after a shower, plus they fold away to stash in a corner/under the bed when not being used.
Stick on hooks. I bought several for dd and they were really useful, we put them on the back of her door, side of the cupboard etc.
If there is room in her accommodation, a thin coat stand. Dd didn't use hers as her room was farily big, but you can get all sorts hung up on one - coats, dressing gown, bags - bulky stuff. I got ours on amazon.
HTH 