I can email you a brochure from a realtor's marketing service on preparing your house for sale, if you'd like (if you want it, please PM me, because I may not find your thread again). I work for a realtor, and her biggest thing is to make sure your house is CLEAN. Make basic repairs, repaint if it's been a while, but don't put a lot of money into upgrades or new carpet, unless it's horrible. Make sure your front and back yard look good -- put some flowers in, mow the lawn, put new house numbers on, maybe paint your front door. Have a good friend walk through the house --someone who will be honest, who will tell you if you have any odors, etc. Declutter. Put away family pictures. Clean off your refrigerator doors. Take as much as possible off your kitchen and bathroom counters.
When you have a showing, go away. Don't be home. Take any showing, even if it's 10 minutes from now -- throw things in the dishwasher to get them out of the sink and leave. Be reachable -- if your realtor's office has to wait for you to confirm a showing, you might lose out on a last-minute one -- make sure your cell phone is with you and the office has that number. Take the showing even if your baby's asleep, your other kid's home sick. Make a habit of making the beds every morning and washing the dishes immediately. If you decide to rent, all of this will help you get top dollar for your rental, too.
Check to see if your town has an "exit tax" -- a lot of communities are doing this -- you have to pay a % of your sale to the town as part of your closing. That could be an unexpected cost. If you're moving a certain distance from this residence for a job change or for work, you may be able to deduct some costs on your taxes.