Thought I'd join this thread (I have read every single post in the first puppy survival thread in anticipation of getting our puppy!) and introduce vikpup who is a mini schnauzer and turned 13 weeks yesterday (exactly the same age as your pup I think towelpintpeanuts!). He has been with us a month and is such a wonderful little family member. He has learned some basic commands very quickly and is playful but calm and relaxed inside when he needs to be (I work from home), and full of energy outside! Toilet training has been easier than I expected, only a couple of accidents over the last two weeks, and he is sleeping through the night in his bed outside our bedrooms. Play biting was a big problem for a few weeks, but he now gives up within a few seconds if we stand completely still, and goes off to find himself a toy instead. I walk him off leash in the small wood next to our house and recall is going really well - haven't faced any major distractions yet though, so not sure how that would go!
However. Over the past week (since just before 12 weeks) he has gone from being completely quiet to barking and growling at other dogs (and sometimes people) when on leash, I am not sure if it is out of frustration or insecurity/fear. I try to distract him with treats but can't really interrupt him when he starts growling/barking/howling and straining to get to the other dog. I think he just wants to get closer or play, but at the same time I don't want him to greet each and every dog as that seems to make for quite stressful walks. I hope he will eventually calm down with more treats. I'm feeling slightly more hopeful this morning though, as he was really calm and good on our morning walk, despite meeting two dogs on leash.
Also, he has started barking in our garden at the neighbours and at the builders who put up our new fence earlier this week, as well as at certain visitors. I really don't want him to disturb and annoy people, so I hope that we will be able to change this. I try to remove him from the garden as soon as he starts barking and then take him back out when he is calm and look at whatever he was barking at, rewarding him for being quiet. Not sure yet whether it is having any effect.
Otherwise, one of the main challenges at the moment is loose lead walking. I try to stand still every time he pulls at the lead, but this really requires patience! A 5 minute walk can take half an hour, not ideal on the school run for example, but I try to remember that it will be worth it in the long run.
Also, it is completely impossible to get him to stand still and to keep him from biting the brush and our hands when we try to brush him. I have absolutely no idea of how to get him to stand still more than for a few seconds at a time. He is going to the groomer for the first time on Monday, so I am hoping that he will magically be a bit calmer for that...
I sometimes feel overwhelmed by all the things that he/we need to practice and learn, but try to remind myself that he is only a baby and these are early days. We are starting a puppy class next week, looking forward to that.