Pricing too high from the start
Homes priced correctly when they first hit the market generally sell closer to the asking price than homes that start to high, then have to adjust downward.
Not basing your price on sold homes
Remember, homes can be listed for any amount. What is most relevant is not the "asking" price but the "sold" price of nearby homes.
"Emotional Value" vs. "Market Value"
Of course, it's your home and you likely have many great memories that were experienced there. keep in mind that potential buyers won't have the same sentimental feelings for your home as you do. Try to stay as objective as you can during the process and it will help you meet your goals.
Refusing to negotiate
Your asking price may want to have some amount of built-in flexibility so you can entertain offers. Keep in mind, even a low offer can be the beginning of a negotiation.