Make sure you know all the steps involved in the selling process.
Don't overschedule. You don't want to become exhausted, so don't try to do everything at once.
Talk to family members about how they feel about selling and moving. Allow concerns to be aired so they can be addressed.
Young children, especially, can feel emotionally attached to a home. Think of ways to make the transition easier. For example, have them draw pictures of how they'd like thier new bedroom to look.
Selling and moving can, at times, be disruptive to the household routine. As much as possible, try to remain consistent with mealtimes, family events, etc.
If possible, get the help you need. Consider hiring a cleaner, home stager, contractor or other professional. Yes, it costs money, but it will help make things less stressful.