i sometimes walk around with an attitude thinking i am the gift!
What to do about it:
Don't be ego-centric. "Don't try to be original, just try to be good." by Paul Rand
Be less risky. Remember, the client has options, i'm not the only one they are talking to. Get to understand their problem and help solve that.
Don't present yourself as the best option, present yourself as the less risky option
Stand up from the crowd. Present your work to the world. Don't just show the end result of your work. Show your work. All the way through. Talk about things like who you are, your processes, and so on. Give the client more to go on in making a decision. Otherwise all the client have to compare is one person's work with the other person's work. Make it possible for the client to get to know you. Give them a reason to care about you. Tell them how you got from "here" to "here" and if say "you work with me this is how it will lay out".
So, diminish risk and create uniqueness and value in what you offer.