There are tons of ways to do it...
I clicker trained Tara to walk on the treadmill. I shaped it by first having her interact with the treadmill while it was off, then run across it like a dog walk in agility (still off), then turn it on to condition her to the noise. Finally, started click/treating for paw touches while it was on and then got her to jump up and run across it. In the beginning I didn't care if she bailed off the front or sides since she was still getting used to it. I kept the speed very slow in the beginning to let her get used to it and only very slowly increased.
She got to the point in this video in maybe 3 sessions of 5-10 minutes, but I think I should have gone a little slower with her.
A few tips that I had sent to some folks while we were training...
- Before the dog tries to get on while the treadmill is moving, make sure he/she will get on while it is still. Dogs will probably be more comfortable if they can walk across the treadmill while it’s stationary before trying it moving.
- This treadmill is relatively quiet, but it is a good idea to make sure the sound isn’t an issue before trying to get the dog on the treadmill.
- 0.5 is the lowest speed this treadmill will go and a nice slow starting speed.
- If you train with food/toys (and even if you don’t normally but want to for this), either would make for a good lure to keep the dog’s head forward and body centered on the treadmill, so using their favorite toy, dinner or lots of small soft treats is a good idea. I actually used baby food to give something to Tara to just take a lick every now and then. I found that she had the most trouble when she would walk like a drunk person and veer from side to side and put her paws on the stationary part, so keeping her centered was important.
- Just learning to walk on the treadmill was exhausting for Tara, so go slow and give them plenty of breaks.
ETA - I think there is a thread somewhere with more info and details, if I can find it I'll come back and post it later.