Also, wear pants. They don't have robe fancy but don't sit around in your pajamas because then you're never really "at work" and you'll never stop being somewhere in the middle.
The people who suggest taking a walk are spot on too. You have a rather small space for being remote. Having a "going to work" routine helps you mentally prepare and the reverse does... well... the reverse. If you like beer/wine/pot/games/etc, getting your favorite at-home vice/hobby going after work is another good mental signal.
Good luck! Stay safe (mentally and physically)!