I've found there are a lot of A-Holes who are producers but then you get to work with someone who reminds you that your work can be fun! It always angers me when I see producers treat people like shit. There's no need for it.

As for getting into the Art dept. I work in Post but I'm sure there are a lot of similarities. Let it be known you want to be in the Art Department when on set. Make connections with the Art Department people and keep in touch eventually they might have an opening for a Trainee.

Also, do as much art dept. stuff as possible! Student films, shorts, commercials whatever you can get. You'll start building relationships on these sets that will lead to future work.

As I said I work in post as an editor so things might be slightly different on the set. But get out there and market yourself.

Hope that helps in some way.