How do you know if your ego got in the way of your performance? One way is to notice where your mental energy is focused. Are you thinking about what other people are thinking about you? Is your mental energy going towards impressing other people? If you notice that you are thinking more about what others are thinking than on the process of your performance, your ego is probably getting in the way of your higher level performance.
If this happens to you, simply take a deep belly breath and bring your mental energy back to focusing on the Energy Fundamentals. That is, focus on your breathing, moving your feet, exuding confidence from your eyes and keeping your thoughts short, simple and positive.