I have sold quite a few cars in my time. I used to buy used cars with some engine problems, or maybe just used cars with some body damage. Either way, I would buy the car, fix it up, and sell it for more profit.
Doing so, I not only sold a lot of cars, but I also bought alot of used cars. I know all the little tricks that car buyers try to pull on the seller to get the car at a cheaper price. Buyers usually try to find things wrong with the car to bring the price down. There is nothing wrong with that, but you need to try and avoid these things so you can get top dollar when selling your car.
One thing you want to do to help avoid this is to change your motor oil and filter. One of the most used excuses to lower a price was because the buyer says he wants to knock some money off to get the oil changed. Do it yourself to eliminate that. Also, fill all your fluids such as radiator fluid, washer fluid, and brake fluid.
People will try and find anything to get you to come down on the price. Another smart way to get all the money you want from the car is to advertise the price a little higher that what you want out of it. That way you have some room for people to talk you down, and your still happy with the amount of money you sold the car for.