Dont let the buyer walk all over you. I give this advice to myself especially if I want to sell my car fast. If the buyer feels like they can walk all over you they will find it easier to negotiate you out of a fair deal (the deal may seem perfectly fair for the buyer but it will be at the expense of your fair deal). If the buyer opens negotiations at a ridiculously low price dont be disheartened. It may be because they are genuinely interested in purchasing the vehicle and want to open negotiations. However, a bad buyer will probably walk away when you make your counter offer because they cant low ball you into a deal that is unacceptable for you.
If the buyer hasnt walked away after you have made your counter offer then I feel like I can sell my car fast . This is the point where the negotiations really become interesting. After this point you might want to bring up something special about the car with each counter offer. That way the buyer will feel less inclined to make their next offer closer to their offer and it will instead be closer to yours. The whole idea is to reach an appropriate compromise. That doesnt mean that your idea for the compromise is any worse than theirs! Remember that both of you are entitled to a fair deal and the buyer is not the one that makes the decision on whether to actually accept the price that they are trying to negotiate. You still have some power in this relationship.
If the buyer doesnt want to come to an agreement that suits me then I consider offering them a deal on specific components of the car to sell my car fast. Tell them you will be happy to remove X component if they will pay Y price (where Y will be pretty close to their offer). This will probably make them want the item you wish to remove included even more and there is a better chance of coming to an agreement that suits you. Dont make threats that might include removing the spare or parts of the engine; that is just silly. Things like sheep skin seat covers or extras you have installed are fine however.