I had the same thing with my first Pi. Miss-A is correct as well. Though there are other training methods to speed up the process, nothing helps more than giving it time and patience. My Pi was a rescue so I got her as a 10 year old, so she has been around the block. She did not let anyone touch her and when she did step up, she searched for the closest branch to escape the stranger. But everyday, I talked to her, fed her, gave her water, fed her treats (also gave me time to figure out her favorite foods) and now, we are inseparable. Though she still has a hard time with strangers. She now lets me do whatever with her! I found out she loves car rides and so we go out to my barn every once in a while and I take her perch and she sits on her perch and watches me groom my horse. In time, you too will make a great team!