All the walls in my last house were cream, viewers seemed to like this as its a blank canvas, could you repaint?
Decluttering is essential, everything off the worktops in the kitchen and nothing in the bathroom on shelves or window sills, hide it all in cupboards.
I actually got a skip delivered before I put the house on the market and it really helped when I actually moved!
Dodgy carpets, get a few cheap rugs.
My kitchen was terrible, clean but needed replacing, estate agent said not to change it as the buyer would do it anyway and I'd be wasting my money.
Little things help like made beds, clean windows, a couple of "plug-ins" so it smells nice, take art off the walls and dab a bit of filler over any holes and paint, clean skirting boards.
Before a viewing, run the hoover round, wipe tops down, polish, take the bin out.
Tidy the gardens, put a plant on the doorstep in a tub.
It's a pain in the arse but worth it.
Do you have a friend or neighbour who could come and critique your house, another pair of fresh eyes would help.