Sometimes the smallest little details make your cars look so much better and in many cases add profit at a 2:1 ratio. When I was younger I made a living buying cheap cars with rips in the seats and dashboards. I would add seat covers and a minor patch kit for the cracks, then turn around and re-auction the car at a respectable profit.

Simple things like

• Spray paint the wheel wells black or use spray on rust proofing to get a thicker finish.
• Spray silver paint on the end of an exhaust pipe
• Cleaning foggy headlight lenses with Turtle Lens Cleaner
• Add paper floor mats after the car is detailed. (go here to get a case of 500)
• Add an air freshener (go here to buy in packs of 10)
• Repair windshield chips. The cost of repairing a windshield is usually less than the amount that buyers will mentally knock off the price if you leave the damage as is.
• Add used tires, this can add the most value per dollar of anything you do

Train your detail crew how to perform these little upgrades.