I loved this post about the importance of being a good negotiator. (See CIO: 7 Career Tips to Help You Negotiate Better.) I had a wonderful manager early in my corporate career who responded to my request for a raise by coaching me through a proper negotiation. When she offered me the job - my first out of graduate school - I was so excited that I screamed, "Yes!!!" into the phone before she could finish making the offer. So when I requested another raise within a year of receiving a 10% raise, she knew my negotiating skills needed help. She could have simply said, "No," and I would have dropped it. Instead, she prompted me to get online and do my research - go find out what someone with my qualifications is earning on average in roles similar to mine. It helped me understand the relative decency of my current salary and go back to her with a more structured, concrete request. I got a 25% increase that time.
Now, we all know it's easy to make big jumps early in your career when 25% more of not so much is still not so much. But the lessons learned will always apply. I was particularly struck by the article's mention of all the sideline implications to being a bad negotiator - you're inadvertently saying you're happy with not so much.
Over the years I have learned to ask for what I want - not what I think I can get. There's generally a big difference.