From one who has SOLD a car over ebay, I can offer this:

1. From ten feet away the paint job on every car looks great. My black '92 Chevy Lumina with 160K miles did. In reality, the hood was moon-cratered with a lifetime of stone chips which would require re-spraying of the entire hood to correct. Unless the seller is also showing extreme close-up photos of the paint in critical areas like the hood, you're really buying a pig in the poke.

2. I have documentary photos (for state registration requirements) of my '84 244GL which had to accompany my application for registerin the car as a reconstructed vehicle. It looks absolutely great. If you saw it in person, however, you'd never buy it. the clear coat has peeled off everywhere and the hood, top and trunk are missing paint and are badly scratched.

3. Clean engines and driver's seats tell far more good things and dirty engines and soiled seats tell something else. these photos are the first ones I look at. If I see a dirty engine bay and a cracked, scuffed, dingy driver's seat, I don't even look at the rest of the auction.

4. There are clues about the car's condition and care hidden in the photos. for example, milage is reported as 86,000. You look at the photo of the instrument console looking from the back seat. Look closely. how much is the brake pedal worn down? A lot? Maybe that 86,000 is the re-built engine, but the body is more like 140,000?

Check for soiled carpets. Stains on seat and door fabric (expecially in tan upholstery, which always appears soiled to me, anyway). Look closely at where the elbows rest and rub on the door fabric. tht stain is telling you how hard the owner has been on this car, or how much "wear and tear" is had seen. What does this mean for the rest of the car?

5. Spy out clues in places like door hinges in photos looking into the door openings. Grimey hinges? Rust? Check body seams at the door bottoms. Rust?

6. With my wife's allergies, vehicles which have seen pets are out. Don't take this lightly. I purchased our '84 Olds Custom Cruiser from a local car lot with it stated in the sales contract oour deposit would be returned and the sales cancelled if, within 24 hours, my wife suffered a reaction to the car following the test drive. In eBay photos, lok carefully are the rear seat and station wagon cargo areas for pet use.

7. Not all sellers know the car. "Wholesalers" rearly admit to knowing anything negative about their inventory. "We just got it in this morning".
Even my car proved to have a few hidden surprises for the buyer, even though I fairly represented it (close up photos of visible pronblem areas, ans statements about known, needed repairs).

8. Up front honesty helps. My buyer (from South Carolina!) said what he appreciated was my willing to show and tell all the faults. He said this chases away many potential bidders (I had just three! and had to run the auction twice due to a deadbeat "winner".) But, it helped him because he knew this kind of car and had little competition.

9. Phone (at least email) the seller. A rapport with a live voice goes a long way more than an impersonal and imperfect computer image. My buyer and his wife rented a car and drove up (to Pennsylvania), stayed overnight in a motel and arrived on a -4 degree morning to pick up my Lumina.

And the car wouldn't start!

Without having the good, personal rapport we had developed through several phone conversations and email exchanges, this would have been very bad. At it turned out, I told my wife to fix them breakfast while he and I put a shot rubbing alcohol into the intake to thaw out the throttle. Once we had it running, he enjoyed a spirited test drive, we had a pleasant breakfast then I took them to a local office of their insurance company.

That would have been a pleasant end to my story. A year later I contacted the buyer. He said he needed to put in an amount equal to what he paid for the car for repairs neither of us had known about.

Caveat emptor. (not the same thing as wishing you "good luck")