I have a couple of horses that I show in obstycle so I need them to pivot and sidepass but can not afford my own trainer so I do it myself. You will want to teach your mare on the ground with a halter and good long lead rope. To get your are to side pass stand in front of her so that she can not go forward I found that a whip with a flat ebnd is the best thing that helped me...you can also do it with a lead rope but it is harder. Just stand in front of her holding the lead to where she can not go forward, then put the whip or lead by her side either making noise with it or taping her side if she doesn't respond to the noise. To get your horse to pivot try holding her lead tight to where she can not go forward and slowly try turning her and getting her use to that fealling.