We prepare our horses for picket line at home where there are not new scary things and they are comfortable, we will start them out just tying them on the picket while we clean stalls, then move up to while we are working other horses in the arena, and eventually work up to an overnight stay on the picket line. We usually have no troubles when we get somewhere then because they have already learned what to do. We give hay bags while at home on the overnighters and do the same out at camp. If its a young horse we dont start them on the picket line we start them on a "patience" pole. We have a huge telephone pole in the middle of our pasture (its just the pole no lines put there for this purpose) that we tie them to to start. That way if they get impatient and rare or throw them selves down there is a less likelyhood of them hurting themselves by puncturing them selves or getting hung. It helps them learn paitence and to tie. BUT there are always those horses that dont do well on a picket no matter how much prep time and work you put into it. I have only had one in my life and it was not an issue with the picket it was an issue with being on the picket with other horses. She was fine by herself on the picket.