M.P.
As an employee, I have always gone into an interview as if I am the one interviewing them. When you have that kind of mindset, the confidence shows. Having interviewed a lot of people, for me, it's 1/2 about accomplishments, 1/2 about confidence. Get a good list of questions together to ask the employer. I am always impressed with people that have done their homework and ask relevant questions about the job and/or company. It means they take it seriously! These are the people that stand out for me.
Hope this helps!