What is my God-given purpose in life?

This is a question I've been struggling with a lot lately. One thing I know is we were all put on this earth to serve him. All my life, I've been surrounded by people who tell me, "God has a plan for your life." It took me a while to believe it, but it's true. Personally, it is easy for me to serve him by serving other. We would all be better off if we all remembered our purpose was to serve him.