Our little bundle of joy was (and still can be) a complete nightmare. we got him a 8 weeks, but he was away from his mother from about 5.5 weeks so never got put in his place and so brought that behaviour to us.... lets just sat after a few months and some very unhappy times for my wife he is starting to settle down. He still does come and just bite us for no real reason, apart from to get our attention, he is 5 months now and has just finished teathing a week ago, and in that week he has stoped mouthing almost completely.

We have noticed that they just somehow get stuff and one hour they are a nightmare and the next they understand and are as good as gold, this has happend with pretty much everything for us.

I would however say, it is likely to take a while (at least 4-6 weeks) before you get the behaviour completly sorted, but here are a few things we figured out about ours that helped reduce the problem/intensity

- try to keep your puppy calm, dont have people pet him all the time, he really needs to be asleep a lot. Our worst time is when people visit and he gets worked up and just wants to bite everything and second if he misses a sleep break, then he just gets more and more tired.
- time outs are great, be it you from him or him from you. Dont make a big fuss about putting him out, if you need to just go out of the room and close the door, or stand up and turn your back on him and ignore him... the more fuss (good or bad) you pay him while telling him off or removing him the more it will incourage him to keep up the behaviour. All atention is good to a pupy lol
- what food do you use, use something that doesnt have artificial stuff in it, we use burns mini bites.

Anyway hope this helps, but choose and aproach and stick with it.