Being nice to people is good. However, making sure you deliver the image they want is more important. I have some experience in this and attractivness only goes so far.
I wrote a blog with tips for actors; however, it applies to anyone in the entertainment business. It could be better than some, because I'm still stuggling and remember all the weird things that successful people forget or don't want to talk about. BTW I get paying jobs.
http://acting76.blogspot.com/