Toni Rosado has selected 10 bad things interpreters shouldn't do to themselves.
I would like to highlight "Lower your fee to keep the client" and "Be timid when negotiating work conditions".
These items harm you and they also hurt the profession, everyone else in the business, that is. Like he wisely says "I am in the business of working less and making more".
Another common bad habit is "Avoid interpreter conferences". These are indeed good opportunities to learn, network and expand business.
http://rpstranslations.wordpress.com/2014/04/01/the-ten-worst-things-that-interpreters-can-do-to-themselves/