You would be surprised at how many simple things really stick out when showing a house. Make sure all light bulbs, door knobs, door handles, light switches and appliances are working and in good shape. Is there any cracking in the walls or ceilings? If yes, maybe patch and sand all of the cracks or chips. Does every wall and ceiling look fresh and clean? Would a coat of paint really help liven up any or all of the walls and ceilings of a home? If yes painting a room yourself is one of the least inexpensive ways to add value to your home.
Does the carpet look worn in certain areas? Would a carpet cleaning make the carpet look better. Of course leaky faucets, leaking roofs or leaking basements should be attended too also. Maybe look at some overgrown shrubs and rip those out and plant a few new shrubs. Do it yourself and save lot's of money on all of these repairs.
If your kitchen is old an outdated, maybe get a few estimates on updating it. Granite counter tops ar almost standard no, and prices have come down a lot. Of course a new roof or new windows could possibly add value also, but it would have to be cost effective.
There are so many ways to increase the value of a home, and not all of them ar major redos or expensive.