1-How to sell your used car?
When selling your car privately, take a cue from dealers and make the car as attractive as possible. Use these guidelines:

Start by cleaning your car thoroughly. Wash and wax the exterior, remove all interior and trunk clutter, vacuum and wipe down all interior surfaces, and clean all the windows. You could have it detailed by a professional to save time.

Replace burnt-out lights or fuses and top off all fluid levels.

Many buyers will want to have your car inspected by a mechanic of their choice. You may want to have your own mechanic inspect the car prior to placing the ad in order to avoid potential surprises closer to sale.

2- Buying tips:
For young and first-time drivers, buying a car can be a very long process. What to buy is a personal decision, but here are a few recommendations. Best-selling models are a wise choice, for several reasons:

Selection: Because so many are sold, there are plenty of used models around, which means you'll get a wider selection of mileage, features, colors and prices.
Repairs: Their popularity means more mechanics are able to repair them, plus their parts are widely available and are comparatively inexpensive.
Reliability: Best-selling vehicles became best-sellers for many reasons — and reliability is a key among those.