I agree with Collieman-don't be too quick to rule food out esp if you have a food motivated dog. There are people in my agility classes that would be in heaven if their dog were more food motivated. I used to be a non food trainer because I considered it a crutch. Yet I was constantly a little dissatisfied with what I trained and expected and the returns I got. SO I urge you to be open minded and not discount it until you try it..and try it correctly. there is a very subtle difference between luring and rewarding. and there is a lot of nuance in doing it correctly so you don't end up with a dog that "decides" to comply. So if you are luring your pug and he sees no food he won't do what you want. you've accidently trained him to respond only if you have food. your job as a human is to trick him into ever guessing is this going to be the time i get a treat? this one? this one??
when i got over my prejudice and listened to some trainers that knew what they were talking about I realized food isn't a crutch and it is not a constant necessity. it is a random/seldom necessity. for a food motivated dog the total lack of reward will cause behaviors to go extinct. they are a what's in it for me creature. for my two dogs food, toys, play, and praise all work so I use them all as rewards.
the reason food is the best tool at a young age especially is that they are not reasoning little beasts at this time. they are more instinct and want and survival. so while you could teach an older dog to roll over it would be very hard to do with a puppy in the absence of food-what's in it for him? praise is something they learn is good over time, they don't even know good dog is good at 3 mos they are just infants. now if you lured your puppy correctly with food you could get him to roll over. I had my puppy rolling over at 3 months on cue with random treats. research shows that especially on very important things like come (which can be life saving) that the cue reward imprints much better on a puppy brain than anything else.
For example my dog is 14 mos old now and in full adolescence, testing the boundaries, and at that age where they forget everything they learned for a while. I don't have much trouble with it because i am home all day and very tricky myself but hubby has a horrible time. The other night he let them out on our fenced patio to potty and she took off barking at a herd of elk. Deep snow and she wouldn't come for him and I knew exactly what she was doing even without seeing. We have a 3 story house to i came down-got the field retriever whistle, went down to the basement and gave her a 3 burst blow for come. She came running.
The reason I tell you this is I haven't used that whistle in over a year - b/c the neighbors don't really appreciate it (really LOUD). Why did it work when hubby was out there with cheese and a toy? Because from the time she was born the breeder trained the whole litter to come to the whistle using food. It is so imprinted on her brain that even though I never use it she remembered when all the cheese and squeaky toys were ignored. She also turned from a herd of elk and ran to me so that says a lot about the imprint power of food on the puppy brain.
the strategy for food training follows. teaching new behaviors like walking on leash lure by holding the treat in position and periodically rewarding. if puppy loses interest you are waiting too long to reward. lure to a sit by moving the treat slowly up in front of puppy's nose and his butt will hit the ground as he raises his head to get the treat. the second his butt hits the ground click/treat. keep this up until he gets it.. mine got it after 3-4 times. Then hide the treats out of site on the counter or in your mouth. do the same luring hand motion. if he sits click grab the quickly accessible treat and treat within 1-2 seconds. no fumbling in bags or pockets. if he doesn't get it use lures a few more times until he gets the hand signal. at 80% success you then add the word cue. do your hand motion and just before he goes to sit say "sit." by this i mean just before he shifts his weight back and bends his back legs preempt the movement with your cue. when his butt hits the ground click/treat. practice and treat at 100% until he gets it and you can drop the clicker pretty quick.
the food you fade slower over time. when puppy is doing a great sit start giving him a treat every other time then every third time. as long as you get good compliance you can fade. do random numbers to he can't predict when. if he stops sitting you went too fast, up the treats again. If you continue to treat 100% all the time you guarantee your failure because the dog will eventually reason- "I'll sit when i want to after i sniff that and pee on that because I always get a treat anyway, I can't lose."
If you fade the treat the dog goes through what is called a pre-extinction burst where he will offer the behavior so willingly and just be obsessive about it. If no further treats follow the behavior will go extinct. Meaning he'll stop sitting. So where you want to keep your dog is somewhere in that hyper compliant stage. give enough random HIDDEN treats to keep the behavior alive. This is where also using play and toys and praise in addition to food is important. puppies need to be taught that all of these things are rewarding too and they should be used intermittently during training to teach and help you judge what works best.
my golden puppy did not want to come inside after pottying because the smell of elk, deer, coyotes, other dogs, and woodchucks etc. were in the yard and much more interesting than even a piece of liverwurst or hot dog. So i hid a toy in my coat (one she didn't like much but was plush so she didn't get it often or she'd destroy it...so it was a novel thing for her). So when offering food didn't work I realized I am in competition with this yard, how do i become more interesting? Offering that toy did it. Working with her instincts and pulling out the toy and tossing it to her was magic. She pranced back up to the door and "retrieved" it for me and then gave it to me for a treat and we went in. My other Golden would love to tug a rope ball back to the door. The 4yo I trained with food and now don't use it much but she'll turn away from the herd of elk and go to the house when I ask so I can handle the puppy. One barking dog is a lot less confusing for all of us.
Hope this helps..sort of stream of thought burbling forth. Have you considered a clicker or puppy class. I strongly suggest a positive training puppy class. It's the best way to socialize a young puppy and help them learn canine manners and to deal confidently with all things they encounter in life. Right now this pup is a little fearless so it's a good time to imprint new things. :dogbiggrin:
since i'm not there and i can't see what you're doing i'm guessing at some of this. i usually always have treats on hand. because with a dog's nose they know we have them. the question they have to ask is now ? now? now? so i often have can cheese on the counter or a cheese stick or jerky in my pocket but i don't give it out that often. you don't say if you use the clicker with your pug but I bet you would get better results if you used one for a while.
separate training sessions as you are doing are good and i would keep that up until puppy is solid on most of the things you want to train. I do separate and group sessions where I ask name sit, name down, and for both dogs puppies down. so they learn that I am asking for a dog to do something and only he one asked is rewarded. the other is ignored but given a chance very soon to earn the treat too.