Pricing your car for selling should be determined BEFORE you buy a car. However, its worth holding off on a fixed selling price until you are totally done preparing it.
Why?
Because many times you may find that the car now runs and/or looks much better than you expected it would when you first bought it and thus will command a higher selling price.
Making MORE CASH on a used car than you expected is a really nice bonus and as you gain experience, you will find this happening more than you ever realized.
So one more key to maximizing your profits is to NOT jump the gun on pricing your car until its totally ready to sell.