My recommendation is a small thing: a trashcan with a swinging lid!
Covers the trash, reduces smells, will prevent trash tetris (sometimes), and very good instead of foot-pedal opening trash cans or trash cans put in a cupboard.
Another thing are toothbrush holders that stick to mirrors. Might jog that memory of needing to brush your teeth!
Wall-mounted keyholder by your door, too. Anything I put on a flat surface will eventually be lost or covered with more junk & papers. My keys are WALL-ONLY!!!
What item(s) have helped you with your struggles?
Big ol’ white board on my door so every time I leave, I have to look at the board so I can remind myself to do shit. Regular and calendar. I originally had the calendar elsewhere, but then I would forget to even change the month :(