Thirdly take ample of photographs from all angles of the car both interior and exterior and post it in the site with all the information needed to give about the car.
Fourthly deal with the buyers alone. Do not let a third person come in between because he will charge commission for his task.
Fifthly the buyers will bargain for the price but since you have already checked the value of your car and you have spent money in repairing and other stuffs include that money in the selling price and keep a little profit and say the price and stick to it. No matter how much the buyer bargains do not sell the car without keeping a profit because in future you will get more buyers. Further keep all the documentation ready for the car.
Ownership, registration, service papers and whatever documentation you have about the item. When the buyer comes to visit and see the car keep it in a proper condition so that the customer is attracted to the item in first sight. Then point all the positive things about the car, do not miss out any single detail. If the customer agrees to buy then handover the documents after he has paid the full amount.