Right! With your room, the idea here to "tune" your room so that it fits who you are; less like some awful combination of a clinic and a jungle, more like a reflection of you. The end result doesn't need to be neat or anything like artistically messy--homely is best.
Put things that belong together, together. You can do this with anything: paper, laundry to be reworn, books, instruments, toys, or stationery. You'll soon have small little groups of things that all live together in the same room.
(It's not just you! Your things are going home, too!)
They can be in piles, stacks, groupings, occupy the same shelf, or line a specific wall.
Spend some time feeling your way around these things: do you prefer to stack all your paper together? Are they the kinds of documents that would appreciate some air? Would it be better to have them in folders where they can live snugly in?
Go with how you feel: each person navigates through the world differently, and your room will feel more like home if the associations that you find in it match yours.
Sometimes a stack of books feels better next to a window, or under your bed. Do as you feel.
Take stock of the room, walking. Only, do so with a lightly-soaped wet cloth (or sponge), and move it around with your foot while you walk.
To prepare the cloth: In a small basin, put a teeeeeeeny amount of laundry detergent powder and put in some water. Most of the stuff on the floor is the same as that on your clothes, so all we need is a little bit of detergent to lift it off the floor for the cloth to carry it away. (As a side note, it's surprisingly effective! And a nice way to make use of something we'd otherwise only have one use for.)
Next: Squish your mop-cloth (or sponge) in the detergentised-water, and squeeze some of the excess water out.
Then: Let it flop onto the floor, and begin to use one foot to swipe back and forth on the floor surface. Use the other foot to move around the room, and make your way across the room like you usually would. The water shouldn't be as soapy as normal laundry water, and there shouldn't be as much residue water (like when a normal mop is used) but still--be careful not to fall!
As you make your way across the room, feel free to squish your mop-cloth/sponge in the detergent-water to remove the grime and renew it a little.
Once you're satisfied, pour away your detergent water, and replace with clean water! Squish your mop-cloth-or-sponge in it, and wring again. Repeat your tour of the room. This will wash whatever soapy residue that's on the floor.
Your floor in now clean!! Nice. If you want, you can leave the floor to dry, or you can rinse the mop-cloth, wring it until it's as dry as possible, and use it to soak up the water that's on the floor. Make sure to wash the mop-cloth out with a bit of soap before you let it dry, too.
Cleaning some other surfaces in your room can be pretty easy.
First: Just take a (dry!) sponge and use it to sweep dust and other things away. The squishiness and rubbery texture of the soft foam sponge is good at picking things up. If your sponge isn't very good at picking things up, you can dampen it a bit (see below).
Next: While sweeping, you can collect the dust-things your sponge is collecting into a dustbin or sweep everything onto a small piece of paper, and then put everything into the trash.
Then: You can also dilute some of your favourite scented soap in some water and squish your sponge in it. It's a nice way to freshen up the scent of the room at the same time. (Before using, be sure to wring it out until it's only damp/mostly dry! You can rinse the sponge in the same water and re-wring it out to refresh some of its sweeping power.)
You can keep a set of these things in your room of choice: put a small tub of detergent powder, 1 cloth, and 1 sponge into your water-basin and leave it near where you work. (You can also sit a bottle of tap water in there.)
That way, if you're in the room, it's simple enough to sit and clean your desk or the floor-area around you while you take a break.