I forgot to add that along with very good photos, a very lengthy description of the known issues, positives, negatives, etc. go a long way too. It's better to keep it real and give full disclosure of everything you can in the ad to save both your time and the other guys time.
I'm currently hunting for an old American classic right now on Craigslist and some of the ads drive me nuts with the lack of details. It's almost not worth the effort to go look in person unless I know a lot about it beforehand, especially when it comes to the fact that a lot of cooler cars are located pretty far away. I don't want to show up at someone's house an hour away just to have to turn right back around and leave due to some major issue that the seller failed to address beforehand.