Declare out loud in the morning as part of your prayers.
God said to speak it aloud, decree and declare it to make it so. That whatever you meditate on, it will fill your heart.
Then out of the abundance of the heart the mouth will speak. God said to start with I am ________ and fill in the blanks of those things He has said to you. Who He has called you to be. What He has called you to do.
Download the declaration sheet with scriptures and declarations, and add your own.