this might be difficult bc mirrors are super expensive, but a cool vintage one could really pull your room together. tbh facebook marketplace would be your best bet for something like that fake flowers would also be cool! like darker colors or maybe even if you could find some that look almost wilted
I would look at shelving units/bookcases from thrift shops or fb marketplace. Most of the ones you’ll see at stores like Walmart or even home goods will be more generic, but u could make those work as well! Reminder that paint exists and you can always add cool details if you’re handy with it, or if you like to do anything with wood or other materials. It would also help fit the aesthetic ur going for :) good luck!!
frames definitely sound like a good idea. i have an absurd amount of posters that could use frames i’d love to have a bookshelf, but it’d have to be one that’s collapsible. we’re required to fully move out every summer and i live too far from campus to make trips (five hours 🥴). maybe target will have something