It turns out the selling yourself is neither about you or what you're selling. It's about the benefit someone else will get after engaging with you. Whether you're in business or in government, we're all in the position of having to share our ideas or ways of doing something and get another person or group to buy-in. It's the nature of how we work.
Maximize your effectiveness by focusing not on yourself but on the results to be gained. Check out this recent article for more on the topic of selling yourself.