You've already gotten quite a lot of good advice. But I completely disagree about not decorating or hanging pictures on the wall. You already have a really nice house that looks very clean and well-maintained. Go a little farther and make it look nicely decorated too. You do not need to fill every wall, but a few extra inexpensive touches will make a room look better. Go look at some model homes for new communities in your area. Those models will have color paint, decorations, and pictures on the walls. Blank is not more appealing to the general public and the big home builders know this.
Maybe it depends on your market, but here in DC people give a lot of value to online photos, first impressions, and cosmetics, and all white blank walls can look minimalist... or kind of like a cheap dorm/apartment/rental. Keep an eye on your local market, see if you can find pictures of what is selling in your area and desired price range. The ones that sell fast, do they all look awesome and pulled-together? Or are they selling fast no matter how they look?
Back in October, we staged our small townhouse with the help of my amazing artsy friend and about $300. Everything we bought I loved and put up in our new house. I've included some pics below to give you an idea of what I mean by staging. We had competing offers within 2 days of listing and closed in <30 days at asking price so I don't regret it at all. Another townhouse on our road listed at our price a few weeks later but didn't show well and just went under contract after 80+ days on the market and for tens of thousands below ours. We fixed everything we could, made the outside look great, rearranged what we already had, and had our friend help us redecorate. We had already painted a lot of walls with color but that wasn't for staging.
Do you have any artsy friends who can help you? Either to help you redecorate, or even to paint you a few pieces/give you artistic photos/create wall art, whatever? Ask everyone around you if they have any nice larger artwork or decor they are not currently using and see if you can borrow it for a few months. You may be surprised at what people have in their basements/attics. Move furniture around and see how that changes your impression of a room. Ask your friends over to do a mock walkthrough and listen to what they comment on.
For decorating: Consider, sometimes the cheapest way to redecorate is to repaint. Especially if the walls are looking a bit dingy. A nice neutral will decorate a wall fast. For art, go to Target, Michaels, Bed Bath and Beyond, wherever. Collect their coupons, and look at their clearance decor. Think beyond "picture" and also look at their wall decor (like mirrors, clocks, sculptures, whatever). You can often find clearance artwork with nice frames for way cheaper than the actual empty frame, and then you can replace the artwork with whatever you want if it is ugly. Check out a thrift store or Habitat ReStore. Sure wallpaper is a great idea inside a frame, or cloth from a fabric store. Or try cheap online poster stores and look for large nature scenes or something to fill the frames. Try to keep frames matching within a space, like all black or all brown. It automatically makes the room look more together.
Some specifics:
- Living room: there is a bookcase over by the fireplace. Can you move that to either under the stairs or where the kids' little desk is? And also, can the fish tank go on top of the bookcase? Or possibly to a trusted friend for the duration? That buffet table is lovely, and would look much better empty.
- The LR furniture all seems so huddled up against the fireplace, and makes it look smaller. Once you are ready to stage and the kids' stuff has moved out, spread the furniture out. Maybe pull out the seating to be more centered in the room? Or perhaps an L-configuration with the two couches.
- The mantel could use a really nice big picture hung on the wall. Or a framed mirror. Those paintings are way too small. Sorry.
- I see a whole bunch of picture frames at the top of the stairs. Reuse those! Just temporarily put new generic pictures on top of the kids portraits... have you or a friend/relative traveled and taken good photos of scenery? Like mountains, forests, cities? Maybe some of those will work especially if there is a common element.
- Dining room: once every small item is removed, looks nice. If the table has seen too much wear, buy a nice cloth tablecloth.
- Master: Don't buy furniture, the room looks sparse but big and functional. Granny rocker - put it in your daughter's room or kids play area if there is space. It can pass as a nursery/little girl rocker with a blanket and a stuffed animal. The personal photo should be removed, but art pieces might look nice. I would just leave the wall above the bed blank if you can't find anything else, you have a headboard and the whole room is very minimalist anyway. If you have a summer weight cover, use that instead (not a blanket, an actual cover). The smooth flat look is more streamlined and gives a better impression.
- Master bath: The pictures over the tub aren't aligned. Sorry. The lace is nice, but pictures in a bathroom aren't as necessary so maybe you can relocate them elsewhere if needed? Also, I see you've unscrewed half the lightbulbs over the mirror. I totally understand, they are always too bright, but it looks bad. Can you find lower wattage? Can they dim? You're gonna want to fix that somehow.
I thank you for providing some entertainment for my quiet evening while the rest of the family sleeps! But I'd better join them. Hope that was some help. Good luck!
Edit note: Attachments didn't quite work out. Reposting below. Sorry!