1. You get your money back for the seller's fees if the item doesn't sell, so don't worry about that.
2. Even if it costs you a little more, list all the pictures you can, because most people look at pictures before reading the item description.
3. State up front EVERYTHING that is expected of the buyer. Tell them if you will deliver the car any distance, tell them if it's up to them to come get it, tell them if you want the money within 10 days of auction close, tell them if you require a 10% deposit within 3 days of auction close...tell them EVERYTHING that you expect them to do after the sale is done.
4. As soon as your auction is over, e-mail the buyer and congradulate them on winning. If you have elected to accept payment when the buyer picks the vehicle up, ask them when they will be able to pick it up, if they will be taking it with them when they pay, etc...
5. In the auction, be VERY specific about what you list in your description. If the car has headers on it, give the name brand and the model number if possible. If it has a Flowmaster exhaust, give the model number. If it has new cams, tell what kind of cams. If it has a tricky door lock or something like that, LIST IT. List ANYTHING that you possibly can think of about the car, it's condition, and it's history. If you start getting bunches of questions from buyers about the same thing that you forgot to list in the auction, go ADD it to your listing so that they don't keep asking you the same things over and over again. Being thorough in your listing is important for two reasons. A.) It lets the buyers know that you are seriously interested in selling the vehicle and you want them to know EVERYTHING about it before they bid and B.) It could save you trouble down the road because if the car has a bad lifter (or something wrong with it) and you don't list it then the engine blows up 3 weeks later you're gonna have the buyer harassing you about it.
6. I would suggest putting in your auction that "All Sales Are Final" and there are "No Refunds-Car Is Sold AS-IS" That will save you from any trouble you might run into also.
7. List in the auction that you will not accept bids from people with negative feedback, and that buyers with "0" feedback should contact you by e-mail before bidding. This will save you from idiots that create screen names just to be dead beat bidders. I guess they must think it's "cool" to show their friends that they bid $30,000 on an item then never bought it. People that have negative feedback ratings aren't worth dealing with at all. If the first few auctions they have been involved in all turned out bad, it's obviously them and not the sellers that had a problem, so avoid them at all costs.
The biggest thing is going to be make sure that you are thorough in your description.
I've sold about 50 things on Ebay with only 1 problem in all those experiences, and even that didn't matter because the second highest bidder bought the item when the high bidder turned out to be a dead-beat.
Good luck bro!!