When you are getting ready to put your home on the market there are many things you want to check and make sure operate & appear as they should. Working with buyers & sellers I've seen the kind of things people notice, and they are not what you'd expect. There are people that can live with a neon green & pink bedroom, but will run from a leaking faucet. Or see prior water damage no matter how small and freak out.
One of the biggest faux pas I see in homes for sale is a lack of cleanliness. Typically it is the things people don't clean on a weekly basis. Such as baseboards, top of the refrigerator, kitchen cabinets, bathroom grout, garages, basements, laundry areas and other places that are normally cleaned at spring cleaning time.
This lack of cleanliness will kill your first impression with potential buyers. I've had some sellers that spent a week doing a thorough cleaning and being so impressed with their home again that they had second thoughts about selling them. And these weren't dirty people mind you. The deep cleaning just makes your house look so much better than it's competition because most people who sell don't take the time or put forth the effort to clean their house fully.
There are many other areas to address. This article on MSN has a very good list with excellent information for each area of interest. See the article below and please let me know if I can ever answer your real estate questions.