Make sure the furniture in each room is not too big for the square footage. If you have to, move a large piece to a larger room while your home is on the market.
If you have a limited budget and older kitchen cabinets, try a fresh coat of paint to spiff them up-and maybe some new hardware.
I would also suggest not keeping the shades drawn during the day; let the light in, it's much more inviting.
My personal 'cleaning' suggestion is about wndows; invest in a professional window cleaner, inside and out. It makes your whole house seem fresh and clean.
Next you need to make the home bright. Replace and/or clean all of your light bulbs. make sure they are all of the highest wattage capable (unless they are for accent purposes only). Clean your windows inside and out. Paint dark rooms a lighter color. Dark houses just don't show well. And homes that don't show well, don't sell well.
Take these two items to heart. You will invest some time and a little money, but you will reap big rewards by selling your home faster and for a higher net price.