1) De-Clutter; you want to show the space your home has and de-cluttering/storing furniture that is not needed is a must! If you are living in the home while it is going to up for sale think of each room as a place to have as much minimal furniture as possible.
For example living room, should have a TV, living room set, and coffee table and/or an end table. Obviously each home and room size can differ, but the minimal is what should be on your mind as a seller.
2) Paint; Interior painting and/or exterior painting is probably the best return on time and money available when selling. Neutral colors, and a good paint job go hand in hand with getting a higher offer from a buyer. Bottom line is if your home has not been painted in at least five years spend the money to have it re-done.
3) Clean The Home (Deep Clean); I cannot tell you have many times a buyer is interested in a home and then as soon as they step inside the only thing that puts them off is the fact it is not clean. This alone will kill a home sale before it even begins. If you want to get your home sold for top dollar it has to be clean. Bathrooms and kitchens are specifically important, but other areas like backyards, and just general things like clean windows make a difference.