>Regardless of how well you prepare, there are times when you run into a difficult client. [snip] What are some of the early signs you would look for that you might it possible to weed out these types of clients?

You mean signs to look for during initial negotiation, to tell you never to start with the client? Well, there may be some, but my approach would be to never turn down the first job for a client, but refuse to work for them again if the project goes bad in some of the ways you described (or other ways you find unacceptable).

FWIW, my boss (I've never done the negotiating myself, just going from what I remember of conversations with my boss), has told me that when he has let a client know they're not being reasonable, and 'threatened' to stop doing work for them (not to stop in the middle of a project, but to never take another project with them), they often come around and become 'good' customers. If they're impressed with the work you're doing for them, which of course our customers always are! :)

Cheers,