I agree with Paddy that salary is the hardest for me to negotiate. On my last promotion, I promised myself that I would be prepared. I researched the pay scales, understood the comprable salary in the field, and agreed with myself on what I was worth. Then when HR called to offer me the position, I was so excited that I said "yes!" and took the salary offered. Why did I fold so quickly when I had such a plan set in place? For that moment, I almost felt like I was back in grade-school and super excited to get picked for a sports team in gym class. But I know that not every woman has this issue. One of my colleagues has no problem arguing for what she wants because she clearly knows what her skills are worth. Like her I can be a bull-dog on some topics and know how to hold my own with a debate but why do I struggle to put a dollar amount on my professional abilities?