Longeing with Harley

I went to work with Harley today. Unfortunately, we didn't work too hard. I'm just learning how to use the longe line, and Harley hasn't been on one in years. We started out quite well. Walking and trotting and transitioning between the two, no problems. Then I tried to get him to canter. Eventually we got a few strides, but it wasn't good. However, I don't know if I'm doing something wrong or he's just being stubborn. We also tried going in the opposite direction. THAT didn't work. He kept pivoting so I couldn't get in the proper position, or he'd try to get me to his other side. Oh well. We'll try again tomorrow.