Seconding the electric tea kettle, basic toolkit, and vacuum. Also you'll want a good mop, the tornado ones are really efficient. Sweep first, then mop. If you keep shoes on a shoe rack then you won't have to worry about cleaning as much/often

If you don't live in an arid or semi-arid climate, a dehumidifier is a must; 60% humidity and above will mold things faster in your kitchen, promote mildew, and just feel hotter in general.

Having plenty of chairs and table space is important. 5-gallon buckets are cheap storage and double-purpose as bottom-tier stools, but stackable chairs are better, and can be condensed to the space of just 1 or 2 chairs. If you find yourself keeping everything on the table, you probably need shelves. (In a pinch, you can use cinder blocks and 1x6 dimensional lumber for shelving, and still pull off a DIY aesthetic.)

Make sure your bed rises far enough off the ground that you can put storage totes or shoeboxes underneath it. Bed risers can help with this but a higher frame is best.

A space heater is a good idea to "heat people, not rooms". For yourself and for guests during the winter, put extra blankets on a couch and chairs.