aaa don’t worry keeping a tidy and clean room isn’t that easy after all, i suggest u start here:

keep all the things u use regularly on a shelf near ur desk

keep things u use less often in boxes stacked somewhere they don’t bother u (remember to put tags on them)

put all ur stationery in a drawer near ur desk

put all ur school stuff together, do this whenever u have a lot of things of the same category (it could be cosplay building stuff in ur case)

if u have a closet or some bed drawers with leftover space use that space to store all the things ur don’t use/need but u still wanna keep (ur stuffed animals, childhood memories etc)

the trick is the more u use something the easier should it be to access it

tidying up everyday can be exhausting so get a huge box with a lid and use it to temporarily store stuff you’re not going to tidy up right now

try leaving the floor as empty as possible so it can be easily cleaned

don’t organize things too much or tidying up everyday will get exhausting, just put things in the right shelf or drawer that’s it

also try not leaving any food or clothes around (tip to remember this: imagine that everything that’s on the floor is going to get trashed)

i understand u might not have or be able to buy some of these things but i hope the rest of my tips can help u, good luck!