I think we have all been there Ken.
I started about 4 years ago, and got stung a few times, but as you say, its all a learning curve.
The biggest thing i found was to build some good contacts. Relationships in this business are key. I got a good realationship going with 3/4 dealers and a couple of old fashion "traders" that you can trust.
I found these key to building my business.I'd know if the guy said it was a "good" car or "a little rough" exactly what he meant.
I also made a couple of contacts in localish similar sales centres. Ideal for swapping the odd overage stock, and trading cars between each other