An old packer trick is to rub Vicks vapor rub in their nose. I didn’t have any with me so I tied my fleece jacket around her neck that had my sweat on it.
Its mainly just time under pack saddle. Another thing that helps young mules is to mix them with old mules. The old mules will teach them with bites or kicks if they get out of line. I had a lead mule that would lift her leg going down the trail if a young mule tried to pass her. If the youngin did not take the hint? They got kicked in the chin. She was the best mule I ever owned. Bought her from the Busted Ass ranch sale in Arlee, Montana. Paid 1500 bucks for her in 96. Everyone laughed at me until it was time to throw elk quarters on and they are having a goat rodeo and my 2 mules are standing in the gut pile ears forward…… they came right off an outfitter pack string.
She trained many of the young mules going forward. Suspension bridges, deer, elk, bear, high line etiquette, going down the trail.
I shot her with my .44 mag when she was blind and failing in the fall one year. She would not have made it through another winter. I bawled like a baby. Hardest thing I have ever done. She was in her 30s. Her name was Mary Lou.