I'm assuming you want to increase the value of your home by a good factor for the money you spend to do it. If that's the case, be careful to avoid doing improvements that don't do that, like spending tons on a new kitchen or bathroom! These things would certainly increase the value of the home, but maybe not by as much as you are going to spend to get them done. If you have a limited budget and are trying to boost your asking price beyond what you are spending to enhance your home, here are my suggestions in order of bang for the buck:
1. Get rid of all clutter.
2. Clean your place till it sparkles.
3. Tidy up your yard
4. Paint whatever looks bad or way outside the mainstream. Remember: you're the only one who finds that sun goddess mural you painted in the kitchen in 1988 charming. And even though you may have shocked the bourgeoisie at the time, magenta may not be a good color for the dining room. People want to see a space that is more or less a tabula rasa to imprint themselves.
5. Tear out any wall to wall carpeting and refinish the floors.
6. If your house is empty, stage it. If it is full, get rid of that stuff.
7. If your home has an odor, open up some windows and some boxes of baking soda. To find out if your home has an odor, ask someone who doesn't live there, preferably your rudest friend!
8. Now fix the most glaring problems with your house, the ones that are the least expensive to fix but shout out to a potential buyer that the place has problems, such as a broken switch plate, or a missing piece of molding.
Every home is different, so your best advice will come from the real estate professional standing in your living room.