Photos: You can have good or cheap, but usually not both. Hire a professional photographer with real estate experience.
By appointment only: If a stranger showed up any 'ol day when you did NOT have your home for sale and "asked if he could come in and walk around" Would you let them in? No. Get their name number and make and appointment for later!
Overpricing: A buyer who has been looking at homes for any length of time, Know value when they see it. They have likely seen the competition and can easily judge market value.
Marketing is not the same as advertising: Have a plan. That includes web, social media, grass roots, print and mailing as well as civic league and neighborhood canvassing. Don't be shy, salespeople who are afraid to intrude have skinny kids and drive cheap cars. You are in sales now!
Lawyer up!: Be sure if you have a lawyer friend, they know real estate law. Seriously!
Answer the phone: If you asked an agent to sell your home and earn a commission and they didn't answer the phone when a prospective buyer called. Fired. Period.
Get it in writing: As noble as a handshake seems, it don't hold water. Get a deposit and make sure it clears.
Early possession: Don't. Period. Ask any experienced pro to tell you a war story and it will likely start with "so the buyers wanted to move in before closing...."