There are many lists of things not-to-do when attempting to sell your home. Let’s expand just a little bit... If you are trying to get top dollar for your home why would you ignore your home's curb appeal? Prune your bushes, mow your grass, pick up your gardening tools, etc. And do not have any type of garbage or junk in your yard. You are trying to attract attention but not negative attention. Your home needs to be inviting for anyone and everyone who sees it.
Side note here: curb appeal not only affects your home value but everyone within eyesight of your home. Don't be 'that' neighbor! (It is similar to being the stinky kid in class, don't go there!)
Crowding a buyer. You should not be at your home because of your personal attachment. In addition to you not being home, remove your personal pictures and effects from your home. Crowding can take place when you aren't even there. Nobody wants to see Aunt Janie staring at them when they are trying to imagine what their home would be like with their belongings in place.
Nobody wants to see your messes or clutter. The best advice I could offer is DE-CLUTTER, de-clutter, DeClutter!! Set your home up for success and remove your mess. If a room is meant to be a formal dining area then take your child's playroom equipment and hide it or store it in a PODs container until you reach your next home.
The last one, SMELLS! It should be common knowledge but you don't want to have someone walk into your home after you have had a cigar party where you served curry chicken and the litter boxes are overflowing. Walk out of your home and come back 5 minutes later and you should be able to discover if your home has a scent. If you are unable to smell this, have friends or even your realtor come in and give you their first smell impressions. Be advised, you may want to put on your 'big boy panties' because their feedback may be a little hard to accept.