One way is to draw your bow, hold on the target then let down. Don't shoot, no matter how bad you want to. Repeat several times. Your target panic won't go away immediately, but this approach does help. It kinda gets your mind to thinking that you are in control instead of the target.

Sometimes it also helps to just shoot one arrow, much like you would in the deer woods. One shot, one chance to get it right.

Ihope this helps a little.