It may take a big chunk of time, but once you get it done, it is easier to maintain.
First of all get rid of any and all trash. That includes papers and old mail that you have not touched for at least three months.
Anything that has not been touched in the last year goes. It may represent something from the past, but it was not important enugh for you to touch in a year. Out it goes.
Make your bed. Use clean sheets.
Get eveything off the floor, and put away. All your clothes folded or hung on hangers, shoes in the closet or tidily arranged. Dirty clothes in a laundry hamper. Then, do your laundry while cleann the rest of the room. After clothes are clean, fold and put away right away.
Everything off your nightstand except lamps and clock, and maybe a small keepsake box. But no papers, magazines, or books.
Then, once all the surfaces are tidied, dust with a clean dust rag and dust spray like Endust. After dusting everything, sweep the floor, and then vacuum.