Most real selling points are fixed and unchangeable (eg location and number of rooms) but there are little details that can make one of two identical houses look more expensive than the other. Door handles, light fittings, rugs for instance can elevate a ‘basic’ room to a more tasteful one, and make it stand out against next door who has left these things as they were. Much depends on the age and style of the house though.
I’ve just put brass art deco handles on the interior doors and have had lots of compliments, but it’s a 1920s house, so they look original. The actual original ones were plain wooden knobs, so the new ones make the house look higher end than it would have been when new. Similarly, plastic light switches and cheap door knobs and knockers can easily be switched out for better ones, and make a difference to the look of the house for relatively little effort.
Rugs, lamps etc can go with you when you move, and don’t overlook rechargeable lamps - you can put them anywhere and if you avoid the very basic ones they look like plug-in versions, so can give the impression that there are more sockets (and therefore placement options) as well as showing off areas of the room better than a harsh overhead light. Try Pooky for decent rechargeable lighting. They even do wall lights/picture lights that don’t need wiring in.
Speaking of lighting, check that all bulbs are the same ‘temperature’. Either all white light or all warm light - never mixed.
Short curtains look cheap, but curtains are expensive and might not fit your new windows, so it might not be worth spending on new ones. If you have short ones and can take them down and manage with blinds it might look better, but you really need to play around with what you’ve got to see what works. Make sure cushions are properly stuffed. Get pads that are a size bigger than the covers so they aren’t droopy. Again they can come with you.
Have fun 😀. Some things will attract some buyers and not others, but balance spending so that most goes on things you can take to the new place when you move.