Getting used to a training partner takes time and lots of listening. Hard to break oneself and the other in! Certainly getting an easy rapport established seems crucial. Paying attention so that the pace is appropriate.
And equipment, of course, but that's a fairly trivial thing.
I tried walking with the ladies once. It didn't work. They were power exercise walkers trying to use energy. I have probably thousands of loaded fast high-efficiency back country miles while doing geology and the like. I simply couldn't use up energy quick enough to really exercise at their speed! Long efficient strides designed to eat up miles contrast with high lift, arm swinging exercise walking.
That's where the rapport comes in. We just laughed about it after a couple of attempts and I went back to cycling at lunch. But if another long-distance backwoods tough guy had been around we'd have been out humping 40 lb packs at lunch.