Dont use white out!!!!! The chemicals and acetone in it can "Fry" the edges of the scratch, making it more obvious, and costing more to repair. A 'Colour Pen" matching the vehicles colour code is best. This will make the scratches harder to notice, and also be a similiar coat to what is on the car, reducing unforseen extra damage. Just apply the pen to the scratch and follow it. Leave to dry fully, then once dry. polish the area (or whole car), and it will look decent as well as providing the required protection.
If a scratch can be felt by your fingernail, then it is too deep to Buff out or to polish away. Generally, either a touch brush or those colour pens are ideal. Buffing/Polishing will remove minor top coat blemishes, and will also remove road grime and contaminants, leaving the paint smooth and clean. Just remember that when you buff, try not to touch the surface just buffed as it will easily mark. Buff one panel at a time, and apply swirl removing polish after each panel to help protect it. deeper scratches often need repairing of some sort.
I have scratches up and down my truck, but when I painted it, I had that in mind and painted accordingly. I done mine in acrylic (easy to rerpair), white and not buffed. I knew I would wreck the paint, and could not see the need in having looking great, just to destroy it.
Hope this helps.