find what motivates him, tug toy, ball, a really excited scratch, whatever. Doesn't have to be treats and don't always use them, make sure your alternating motivators. What are you teaching, basic manners, commands or tricks? For things like impluse control just use things like doorways, food bowls and have him sit quietly. If he can't sit quietly he can't go through door way/can't have his food. He needs to learn some patience which will help with the training sessions. (not in a bad way, same with people, we lose focus very easily!) With the clicker make sure you're quick enough. You have about 3 seconds to click, the sooner the better. A lot of people fumble with the clicker and it gets harder for them so they get confused/frazzled which translates down the leash. Just a thought, sometimes we do this unknowingly.
As for getting him motivated, once again figure out what his favorite thing is, and play during training sessions. Like "tug tug tug, 'watch me', great eye contact!! throw ball, get ball back, tug 'sit', good boy!" etc. Just like kids if its not a "training session" but fun and games they will become more motivated and so will you
Which is why I do musical sit, hide and seek and red light green light with the doggies in class
Keeps me and the pet parents from going crazy haha
As for getting him motivated, once again figure out what his favorite thing is, and play during training sessions. Like "tug tug tug, 'watch me', great eye contact!! throw ball, get ball back, tug 'sit', good boy!" etc. Just like kids if its not a "training session" but fun and games they will become more motivated and so will you
Which is why I do musical sit, hide and seek and red light green light with the doggies in class