When you are in a large crowd of people and start feeling anxious, the best thing to do is to go to anyone who is alone and start a conversation. The idea here is to create your own little group so you can focus within that group.
Try not to see the big picture. Don’t see the island of people. Be in the now. Be in the present. Be in front of whoever is in front of you.
If you are not being forced to go where there is a large crowd, you can always just try to avoid it. There is no need to purposely make yourself conquer it unless you feel you need to. In realizing and accepting that you do not have to overcome crowd anxiety you can ease added pressure that you may be putting on yourself.
If you want to conquer it, start forcing yourself to go to large events and focus on the little quadrant that you are in.
If you are sensitive to energy, you may feel like it is too much energy all at once. You may feel like the other people are leeching energy from you. Try to block off your energy so you are not absorbing for anyone else. One method of doing this is by white lighting yourself. White lighting is done by taking a moment before you go to an event, then close your eyes and imagine a white light over your head that slowly moves from the top to your feet and back to the top. It will work wonders to keep your energy protected. This is not a permanent shield and will need to be repeated whenever you feel others can affect your energy.