Control your ego by knowing that you are important to you and that you are not important to others. This realization will keep your elephant well mannered and at times philosophical.
A healthy ego is a good thing. You want your elephant to be as big as your elephant can be. You want your elephant well fed, well groomed, and powerful. You want your elephant to be confident. You must believe in yourself. You must build your confidence. It is only with a strong sense of self that you can put your clients first and do a good job for them. Do you think your clients will be better served by some wilting wallflower, afraid to speak up for them, or by someone who will be strong for them because they are strong for themselves? This is where folks get things mixed up. They think that by serving others they must take a backseat. They think that blind obedience is good obedience. They think that clients want to always hear yes and to never hear no. Clients want a champion. They want a knight in shining armor. They want someone to protect and serve. And they want that person to be confident in whom they are.