Put a bunch of bookcases behind you with some books and some vases. Look at the Colbert show for tips.
If you can’t do that, my suggestion would be to paint one blank wall a color. Nothing too vibrant, but dark looks better on camera. Navy blue, dark teal, dark green or dark purple. Or if you’re not willing to go out to get paint, you could hang some some curtains. Make sure they’re ironed if they’re wrinkled.
Here’s what looks bad on video: any clutter at all. Even the tiniest pile of clutter looks absolutely horrible and much worse than it does in person. Create a little stage with as little detail as possible. If you have something like a credenza behind you, put a picture of your family and maybe a vase or bookend with a couple of books. That’s it. Make sure there’s no dust at all or anything dirty. It will show much worse on video. Clean everything behind you. If there’s a picture, clean the glass. Make sure there’s no mirrors showing or glass reflecting clutter opposite you.
If you have a picture behind you, make it as bland and generic as possible. A landscape or a flower. Cut something out of a magazine or a calendar and matte it with an old matte. It will look fine as long as the paper isn’t see through. If the picture is something simple it looks better.
You could take a photo on your phone of a family member or pet and print it. Like a big portrait in black and white with a white matte board framing it. If you do this, make it a closeup, not a head to foot picture. Head and shoulders looks much better. The closer the closeup, the better it looks. If it’s a pet, get the whole body but as little background d as possible. Take the picture with as much light as possible, bring in lamps from all over the house and point them at your subject. Point the light down into the person’s face, they’ll look better. If you can stand above them (or on a ladder) it’s more flattering. Make sure the background is totally plain with no details. A white or colored solid wall is a good background.
Take a picture of your finished “set” on your phone. If there’s any dirt or clutter showing it will jump out at you. You may find you have to keep removing things. Less is more.
Look at pictures of expensive houses. What do you see? One, two, or no more than three LARGE objects. A large vase on a big table to the side behind you. A large picture on the wall behind you. Maybe a clunky lamp with some volume to it. That’s it. Nothing else. Don’t overdo it. Expensive is bare. Clutter looks poor.
Look around your house. Look at things as if they were props. A rectangular kitchen table behind you against the wall can make a credenza. Possibly a sofa table if it’s plain and fairly long.
Wear business wear or casual business wear including pants. If you have to get up and you’re not wearing pants you’re screwed. And you might have to get up to fetch something.