training starts the minute you get your dog. they start to learn who you are. sit, down and stay at 12 weeks old that's impressive. 12 weeks is young. my boy didn't any formal training untill he was 4 months old. he was in puppy classes at 10 weeks old. we got him when he was 9 weeks old. his first training was house breaking. we never used paper. we took him out alot. he was outside every 15 minutes graduaally increasing his time untill we got him to every 2 hours. then every 3 hours and on untill he could stay crated over night. we only trained one thing at a time. whatever it was we were training we did one thing at a time. we train 3 to 5 times a day but for short periods of time. 10 minutes a session worked for us. now at 10 months old he sits, stays, doesn't walk out of the house even when the door is wide open and that's with people calling him or calling him with their dogs in our yard, downs, he takes hand signals. we don't have sidewalks, our lawn goes down to the road. he won't walk into the road whether he's on our lawn or the neighbors. we also train him in the house and outside, day or night. i guess he's always in training. the cool thing about his training is we talk to him. i mean talk to him like he's human. he responses 97% of the time without me having to repeat myself or raise my voice. i think you to train through the puppy mode as you call it but they do have to have their puppy moments, it's only natural. i never train to break a dog or to dominate them. i partner with them. that fact that you can train them is dominance. if my boy initiates play i do it. when i don't want to play anymore i say "no more" and that's it. he stops. sometimes he'll come over and lay his head or your lap or he'll give you his paw. i take that to mean he wants attention. so i give him some pats, belly rubs and he's good. he doesn't do it often but i like it when he does that. what's heavy training? one thing at a time and i think he'll do whatever you want him to do. are you training your dog yourself or do you have a trainer? good luck, you have lots of time to train new things. something tells me by the time your dog is 10 months old he's going to be doing more things than mine at that age.