It can be hard to define the specific problems that stand in the way of a good presentation of an interior.
Let's start with the presumption that you're the photographer and not an interior designer hired to do a transformation.
There are some minor things you can do to help make the appearance better than the reality.
You probably don't need to be reminded to balance the benefit from this work against the cost of your time spent.
Start with the solutions that require the least time but have the highest payback in terms of improved photographs.
If you know you're facing a problem room, you may be able to prepare by bringing some items you'd like to see in a nice room:
flowers, decorations, art, and even small articles of furniture.
I have brought nice lamps and throw rugs when I knew they'd be needed.
Remove clutter, straighten furniture
Improve a room by removing clutter.
No matter how interesting knickknacks may be, they can look shabby and confusing on film.
Uncluttered space looks larger in pictures, and this is an important fact to keep in mind before you make your first exposure.
Remove clutter to another room, then replace things after you're finished.
Real estate customers prefer to see some blank areas where they can imagine their own articles.
Simple, clean look
Next, straighten up: crooked window shades and curtains, lamp shades, picture frames, throw rugs, sofa pillows -- all can show up glaringly in a photograph.
Remove excess furniture so the room isn't crowded, and look for worn, damaged, or mismatched furniture.
You may be able to bring in furniture from another room to substitute for essential pieces that exhibit problems.
Otherwise hide them by placement, or move the camera position.
Remove unneeded throw rugs, but add throw rugs to avoid distracting floor defects.
A simple, clean look in your photograph makes it easier for the viewer to comprehend.