We've just sold, and viewed a fair few.
We saw one with the whole room full of craft stuff, literally a tiny square of floor to stand in...it obviously wasn't in the photos. The rest of the house was reasonably tidy. And we still liked the house...(it wasn't the one we went for in the end but it absolutely wasn't off the cards due to clutter).
I'd ensure the kitchen is clean and tidy - I wouldn't necessarily sort the cupboards, but ensure they aren't overflowing with stuff falling out - I open the cupboards when viewing - not because I'm nosy at stuff but to gauge size, condition and see any neat features like lazy susans or pan drawers.
Similarly the bathroom, ensuring its clean and uncluttered.
Also, where the boiler / hot water tank are - not necessarily clear of stuff, but reasonably presentable that nothing falls out.
Make the beds
And put the laundry away.
The rest can be looked past to a point. Honestly, if I liked the house...seeing your kids toys overflowing from a kallax unit, your 101 knick knacks, and cat-scratched sofa isn't going to massively put me off. If I hate it, no amount of staging is going to help.